ATTI DEL CONVEGNO GEOSED

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2 Con il contributo della Provincia di Livorno e con il patrocinio della Regione Toscana e della Provincia di Siena ATTI DEL CONVEGNO GEOSED Siena, settembre 2007 A cura di F. Sandrelli, M. Aldinucci, E. Capezzuoli & L.M. Foresi Comitato Scientifico: M. Aldinucci, M. Benvenuti, E. Capezzuoli, G. Cornamusini, A. Costantini, E.A.C. Costantini, L.M. Foresi, A. Gandin, A. Lazzarotto, R. Mazzei, V. Pascucci, M. Sagri & F. Sandrelli Allestimento testo e progetto grafico: A. Mancini, A. Sestini & B. Terrosi In copertina, per gentile concessione dell Accademia dei Fisiocritici di Siena, Abbozzo della Carta Geologica della Provincia di Siena di Giovanni Campani, 1865

3 ATTI DEL CONVEGNO GEOSED - SIENA 2007 INDICE ALDINUCCI M., GHINASSI M. and SANDRELLI F. The latest Pliocene-Pleistocene alluvial deposits of the eastern Siena Basin (Tuscany, Italy): facies and depositional architecture ALDINUCCI M., PANDELI E. and SANDRELLI F. Tectono-sedimentary evolution of the Late Paleozoic-Early Mesozoic metasediments of the Monticiano-Roccastrada ridge (southern Tuscany, Italy) and their relationships with the coeval units of the Northern Apennines. 07 ANDREUCCI S., PASCUCCI V., CLEMMENSEN L and MURRAY A. Stratigraphy and paleogeography of north-west Sardinia over the last 150 ky, based on OSL dating BENVENUTI M., CARNICELLI S. and CIAMPALINI R. L'evoluzione idrografica quaternaria nell'area di Massa Marittima (Toscana Meridionale) rivelata dall'integrazione di analisi geomorfologiche, paleopedologiche e stratigrafico-deposizionali.. 09 BERTINI A., MINISSALE A., RICCI M. and VASELLI O. Pleistocene travertines of central Italy: paleoenvironmental reconstruction from pollen and stable isotopes BROGI A. and LIOTTA D. Il Bacino miocenico di Radicondoli nel quadro dell evoluzione neogenica dell Appennino Settentrionale. 11 CACCHIO P., FERRINI G., DI PRINZIO G., ERCOLE C., CONTENTO R., DEL GALLO M. and LEPIDI A. Un possibile contributo microbiologico nella deposizione di moonmilk calcitico nella Grotta Nera (129 A) (Pennapiedimonte-Ch) 13 CAPEZZUOLI E., GANDIN A., PEDLEY H.M. and SANDRELLI F. Fluvial barrage calcareous tufa systems as potential markers of quaternary uplift in southern Tuscany: a case from the Chianti Hills. 14 CIARCIA S., MITRANO T. and TORRE M. Tectonic control on sedimentary evolution in the Ariano Basin (lower Pliocene, southern Apennines, Italy) CONTI S., FONTANA D. and MECOZZI S. Seep-carbonates and fluid expulsion processes in the Miocene of the Northern Apennines. 18 CORNAMUSINI G., BONCIANI F., CALLEGARI I., CONTI P., FORESI L.M. and MASSA G. Stratigraphy and tectonics of the Neogene-Quaternary minor basins of the inner Northern Apennines: the Tafone Basin (Romani Mts., southern Tuscany-northern Latium)

4 ATTI DEL CONVEGNO GEOSED - SIENA 2007 CORNAMUSINI G., IELPI A., CALLEGARI I., BONCIANI F., GUASTALDI E. and TONINI A. Stratigrafia e modellizzazione 3-D di un bacino continentale intermontano: il Bacino pliocenico di Santa Barbara (Valdarno superiore, Toscana).. 23 CORNAMUSINI G., IELPI A., CALLEGARI I. and SANDRELLI F. I depositi di avanfossa del settore orientale dei Monti del Chianti (Formazione del Macigno): nuovi dati stratigrafici e composizionali COSENTINO D., CIPOLLARI P., FUBELLI G. and GLIOZZI E. Age of the uppermost paleoshorelines in the middle Tiber valley COSTAMAGNA L.G. and BARCA S. General frame and development of the late Carboniferous to early Middle Triassic continental basins of Sardinia. 33 COSTAMAGNA L.G. and RONCHI A. Facies analysis and paleoenvironments of the Lower Permian molassic Perdasdefogu Basin (E Sardinia) COSTANTINI E.A.C. and NAPOLI R. Applying the pedostratigraphic level concept to geological mapping DALLA VALLE G., GAMBERI F. and MARANI M. Confined turbidite systems: the case of the eastern Sardinian margin. 40 DE FALCO M., RUBERTI D. and VIGLIOTTI M. Alluvial plain stratigraphy and the Volturno River dynamics near Capua (Caserta) 42 DI STEFANO A. and LONGHITANO S. Sedimentology and biostratigraphy of the lower-middle Pleistocene sedimentary succession of the Ionian Peloritani Mts (NE Sicily).. 43 FIDOLINI F., GHINASSI M. and PAPINI M. Non-classical turbidites in the Macigno Formation: the arenarie zonate deposits (Riomaggiore, La Spezia, Italy). 44 FORESI L.M. Geology and stratigraphy of the Pianosa Island GAMBERI F. and MARANI M. The impact of source area, shelf width, basin gradient and base level variability on deep sea deposition (Gioia Basin, southeastern Tyrrhenian sea).. 46 GANDIN A. Petrological investigations on Travertines and Calcareous Tufa in southern Tuscany

5 ATTI DEL CONVEGNO GEOSED - SIENA 2007 GHINASSI M., COLONESE A.C., DI GIUSEPPE Z., GOVONI L., LO VETRO D., MALAVASI G., MARTINI F., RICCIARDI S. and SALA B. The Late Pleistocene sedimentary record from the Romito Cave archaeological site (Calabria, Italy). 48 GRASSO M., MANISCALCO R., DI STEFANO A., GENNARI R., GROSSI F., MANZI V., ROVERI M. and STURIALE G. The Balza Soletta section (Corvillo Basin, central Sicily): an example of second cycle Messinian gypsarenites and lago mare deposits IACCARINO S. and TURCO E. Paleoclimatic and paleoceanographic variations from the Langhian up to the Messinian in the Mediterranean and comparison with low-latitude Atlantic Ocean. 50 LIRER F., HARZHAUSER M., PELOSI N. and PILLER W.E. Middle-Late Miocene record from Mediterranean and the Paratethys area: two examples for long-period variations in the Earth s obliquity and their relation to third-order eustatic cycles 53 LONGHITANO S., SABATO L. and TROPEANO M. Cross-stratified hybrid arenites from the Pliocene Tricarico succession (southern Apennines): influence of tidal currents and high-frequency relative sea-level changes onto large-scale subaqueous dunes MANZI V., LUGLI S., ROVERI M. and SCHREIBER B.C. The origin of the Messinian Calcare di Base (Sicily, Italy): evaporative but clastic MEROLA D. and SARTI G. The use of foraminiferal tests as bio-drifters: a new tool to define longshore sediment flows. An example from Pisa coast (Tuscany, Italy) MONEGATO G., FARANDA C., GATTO R. and LIGIOS S. Paratethyan faunas in the Tortonian succession of the CARG-FVG S6 Col Vergnal drilling (Friuli, NE Italy) MORETTI M., OWEN G. and TROPEANO M. Soft-sediment deformation induced by sinkhole activity in shallow marine environments: a fossil example from the Calcarenite di Gravina Formation in the Monopoli area (late Pliocene-early Pleistocene, Apulian foreland, southern Italy).. 61 MORSILLI M. and MORETTI M. Trigger mechanism recognition of the soft-sediment deformation in the upper Messinian deposits of the Gargano promontory (Apulia, southern Italy).. 64 MOSCATELLI M., RASPA G., STIGLIANO F.P., VALLONE R., PATERA A., MANCINI M., CAVINATO G.P. and MILLI S. Geological and geotechnical characterization of the subsoil of Roma (Italy): spatial modelling of the upper Pleistocene-Holocene alluvial deposits by means of multivariate geostatistics 66 4

6 ATTI DEL CONVEGNO GEOSED - SIENA 2007 NALIN R. and GHINASSI M. Siliciclastic vs. Carbonate sedimentation in a low energy embayment: the Pliocene Val d Orcia Basin (Tuscany, Italy).. 67 PASCUCCI V., CARTA A., ANDREUCCI S. and CAPPUCCI S. North Sardinia sandy shore human impact and preservation: the case of La Pelosa Beach.. 68 PEDLEY H.M. Environmental controls on freshwater carbonate (tufa) deposition.. 71 PEPE M. Geological features of the outer border of southern Apennines, between S. Mauro Forte, Oliveto Lucano and Accettura (Basilicata-southern Italy) 72 RIFORGIATO F., FORESI L.M., ALDINUCCI M., MAZZEI R., DONIA F., GENNARI R., SALVATORINI G. and SANDRELLI F. Foraminiferal record and astronomical cycles: an example from the Messinian preevaporitic Gello composite section (Tuscany, Italy).. 74 RIFORGIATO F., FORESI L.M., ALDINUCCI M., SALVATORINI G., MAZZEI R. and SANDRELLI F. The Miocene/Pliocene boundary: cyclostratigraphy and biostratigraphy from Cava Serredi section (Fine Basin, Tuscany-Italy).. 75 ROVERI M., LUGLI S., MANZI V. and SCHREIBER B.C. The sicilian record of the Messinian salinity crisis: a sequence-stratigraphic approach. 76 SAGRI M. Variazioni climatico-ambientali del tardo quaternario nella regione dei laghi (rift etiopico): contributo della geologia del sedimentario STEFANI C. and GRANDESSO P. Reading paleogeography from lithostratigraphy: the example of the Belluno area. 81 VERDUCCI M. Micropaleontological and biogeochemical proxies for paleoclimatic and paleoceanographic reconstructions: the Middle Miocene climatic transition in the Southern Ocean (ODP hole 747A - Kerguelen Plateau). 82 ZECCHIN M., BRANCOLINI G., TOSI L., PIZZETTO F. and BARADELLO L. The architecture of the Holocene succession in the southern Venice lagoon: an example of the application of very high resolution seismic data. 86 ZEMBO I., PANZERI L., GALLI A. and BERSEZIO R. New chronological constraints on the sedimentary evolution of the Quaternary Agri Valley Basin (southern Apennines, Italy)

7 THE LATEST PLIOCENE-PLEISTOCENE ALLUVIAL DEPOSITS OF THE EASTERN SIENA BASIN (TUSCANY, ITALY): FACIES AND DEPOSITIONAL ARCHITECTURE M. ALDINUCCI 1, M. GHINASSI 2 and F. SANDRELLI 1 1 Dipartimento di Scienze della Terra, Università di Siena, via Laterina 8, Siena (Italy) 2 Dipartimento di Geoscienze, Università di Padova, via Giotto 1, Padova (Italy) The Middle Pliocene uplift of southern Tuscany resulted in the emersion of the marine Siena Basin, where Quaternary alluvial deposits locally accumulated. In this contribution we present the stratigraphic architecture of these deposits as revealed by facies analysis and compositional studies performed in one of their best exposure area (Castelnuovo Berardenga area), with emphasis on depositional processes and controlling factors. Two main unconformity-bounded units (S1 and S2) have been recognized in the post-middle Pliocene deposits. Unit S1 consists of two geographically separated bodies (S1a and S1b). Sub-unit S1a is an elongated body of fluvial deposits unconformably overlying Pliocene marine sands and pre-neogene bedrock. This unit is interpreted as an incised-valley fill sourced from the Chianti Ridge, (the eastern margin of the Siena Basin). Floodplain fines contain continental gastropods ranging in age from Late Pliocene to Recent. Sub-unit S1b comprises coalescent alluvial fan deposits resting unconformably onto Pliocene marine sands. Unit S2 unconformably overlies the unit S1, the Pliocene marine sands and pre- Neogene bedrock. This unit consists of alluvial fan and fluvial deposits fed from the Chianti Ridge. In the study area, the alluvial fan and fluvial deposits show a paleotransport direction transversal and parallel to the Chianti Ridge, respectively. Correlative alluvial deposits exposed in the surroundings contain Acheulean (Middle Pleistocene) artefacts. Although the poor age constraints, regional geological data (i.e. comparison with the nearby Valdarno Basin) and stratigraphic architecture of the investigated deposits suggest the following post-middle Pliocene depositional history: 1 - relative sea-level fall with development of an unconformity at the top of the Pliocene marine deposits characterized by valleys formation (late Middle Pliocene-Late Pliocene); 2 - increase in sediment supply, promoted by the uplift of the Chianti Ridge and a coeval climatic change, with consequent aggradation within previously formed valleys (Unit S1a) and progradation of alluvial fans (Unit S1b) in the interfluve areas (latest Pliocene-Early Pleistocene). 3 - uplift of the basin margin (possibly enhanced by a climatic change) and formation of the unconformity at the top of Unit S1 with no pronounced erosional relief; 4 - fluvial aggradation and alluvial fan progradation (Unit S2) related to a readjustment of the equilibrium profile (Middle Pleistocene). Moreover, beyond the regional significance, the present study documents a kind of incised-valley (Sub-unit S1a) entirely filled with fluvial deposits and whose incision (relative sea level fall) and filling (increase in sediment supply forced by tectonics and climate) are not genetically related. 6

8 TECTONO-SEDIMENTARY EVOLUTION OF THE LATE PALEOZOIC- EARLY MESOZOIC METASEDIMENTS OF THE MONTICIANO- ROCCASTRADA RIDGE (SOUTHERN TUSCANY, ITALY) AND THEIR RELATIONSHIPS WITH THE COEVAL UNITS OF THE NORTHERN APENNINES M. ALDINUCCI 1, E. PANDELI 2 and F. SANDRELLI 1 1 Dipartimento di Scienze della Terra, Università di Siena, Via Laterina 8, Siena 2 Dipartimento di Scienze della Terra, Università di Firenze, Via La Pira 4, Firenze In the Northern Apennines, rocks of Late Carboniferous to Carnian age unconformably overlie pre-late Moscovian successions which were deformed and locally metamorphosed during the final consolidation of the Variscan Orogen. The Late Carboniferous to Carnian successions were affected by Alpine tectono-metamorphic events and are now preserved in the deepest tectonic units of the Northern Apennines (Tuscan Metamorphic Units). In southern Tuscany, they are extensively exposed along the morpho-structural alignment referred to as the Monticiano-Roccastrada Ridge. Despite the Alpine tectonic and metamorphic overprints, the sedimentary features of these Late Carboniferous-Carnian rocks are still recognizable and suggest that they represent the infill of a variety of continental to marine, long- to short-lived basins located in the Tuscan paleogeographic portion of Gondwanaland. The review of the literature, improved with new stratigraphic data on the Late Paleozoic units cropping out along the Monticiano-Roccastrada Ridge, led to provide a paleogeographic and stratigraphic scenario more complex than previously known in southern Tuscany. Six main successions marked by basal unconformities can be pointed out. They are, from oldest: the 1) the Sant'Antonio succession (Moscovian); 2) the Spirifer-bearing Schists succession (late Moscovian-?early Cantabrian); 3) the Farma succession (Late Permian-?earliest Triassic); 4) the Fosso Pianaccia succession (latest Permian?-earliest Triassic?; 5) the Civitella Marittima succession (Early Triassic-early Ladinian?); and 6) the Verrucano s.s. succession (late Ladinian-Carnian), which represents the base of the Triassic to Lower Miocene Alpine sedimentary cycle linked to the evolution of the Adria passive margin. With the exception of the latter, each succession can be considered as a synthem, since the regional-scale extension of their bounding unconformities. Therefore, before the onset of the main Triassic rift phase (recorded by the Verrucano s.s. succession), five main tectono-sedimentary events are recorded in the MRR Moreover, except for the Fosso Pianaccia succession (interpreted as the continental infill of erosional depressions), stratigraphic-sedimentological evidence along with the regional geodynamic framework, all suggest that extensional/transtensional tectonics was the main controlling factor, producing sedimentary basins where continental to marine successions deposited unconformably over pre-late Carboniferous rocks and/or earlier successions. Moreover, the relationships of such sequences with the others defined elsewhere in the Northern Apennines have been redefined. 7

9 STRATIGRAPHY AND PALEOGEOGRAPHY OF NORTH-WEST SARDINIA OVER THE LAST 150 KY, BASED ON OSL DATING S. ANDREUCCI 1, V. PASCUCCI 1, L. CLEMMENSEN 2 and A. MURRAY 3 1 Institute of Geological and Mineralogical Science, University of Sassari; C.so G. M. Angioy 10, Sassari Italy 2 Geological Institute, University of Copenhagen; Ø ster Voldgade 10, DK-1350 Copenhagen Denmark 3 Nordic Laboratory for Luminescence Dating, Department of Earth Science, University of Aarhus, Risø National Laboratory, Dk-4000 Roskilde Denmark The Alghero coast (NW Sardinia, Italy) is characterized by a well exposed silicoclastic Upper Pleistocene succession. It is composed from the bottom up by coastal aeolianites (U1), fossiliferous gravel beach deposits (U2a), sandy beach deposits (U2b), and coastal aeolianites (U3). These deposits are grouped in four units separated by three erosional unconformities. The unconformities separating unit1 from unit 2a and 2a from 2b have been interpreted as transgressive surfaces (TS1 and TS2), whereas the unconformity between unit 2b and unit 3 as a regressive surface (SB1). All but unit 2a have been dated using Optical Stimulating Luminescence method (OSL). The resulting ages are: U1: 151 ± 11 ky; U2b: 97 ± 7 ky; U3basal: 77 ± 7 ky; U3top: 47 ± 3 ky. On the basis of these results U1 is referred to OIS6 oxygen isotope stage (Riss glacial-stage; 151 ky). During this stage the sea level was lower than the present, most of the shelf was exposed and aeolinites developed inland. The U2a is referred to OIS5e (Eu-Tyrrhenian interglacial-stage; 125 Ky). In this interglacial stage sea level was 6 meters higher and climate was warmer than the present. The coast was characterized by rocky cliffs with several coves and gravelly pocket beaches. The U2b is referred to OIS5c (Neo-Tyrrhenian interglacial-stage; 100 Ky). During this interglacial stage the sea was at the same level of the previous and coastal zone was dominated by prograding sandy spits and beaches. The U3 ranges in time from 80 Ky (OIS4) to 45 Ky (OIS3); that is, the Würm glacial-stage. During this glacial stage sea level dropped down up to -120 meters below the present, the shelf was widely exposed and extensive aeolinite fields developed inland. 8

10 L'EVOLUZIONE IDROGRAFICA QUATERNARIA NELL'AREA DI MASSA MARITTIMA (TOSCANA MERIDIONALE) RIVELATA DALL'INTEGRAZIONE DI ANALISI GEOMORFOLOGICHE, PALEOPEDOLOGICHE E STRATIGRAFICO-DEPOSIZIONALI M. BENVENUTI 1, S. CARNICELLI 2 and R. CIAMPALINI 2 1 Dipartimento di Scienze della Terra, Università di Firenze 2 Dipartimento di Scienza del Suolo e Nutrizione della Pianta, Università di Firenze Vengono presentati nuovi dati sull evoluzione quaternaria del drenaggio nell area di Massa Marittima (Toscana Meridionale). Lo studio si basa sull integrazione di dati geomorfologici, paleopedologici e stratigrafico-sedimentologici, rilevati su una successione clastica di generica età quaternaria, affiorante nel Pian della Ghirlanda, depressione di forma circolare a NE di Massa Marittima. Il bacinetto, occupato da paludi bonificate, è endoreico, una condizione verificatasi in altre fasi della sua storia geomorfico-sedimentaria. I depositi riferibili al Quaternario giacciono in discordanza su un substrato indicativo del contesto strutturale Liguridi su Serie Toscana Ridotta, caratteristico della Toscana Meridionale. I depositi quaternari vengono suddivisi in tre principali gruppi stratigrafici che riflettono altrettante fasi di aggradazione interrotte da due principali fasi di incisione. La successione più antica, presente sul lato orientale e spessa in affioramento circa 60 metri comprende: 1) brecce sottili di versante ad elementi arenaceo-pelitici passanti a sabbie, peliti, talora lignitifere, e carbonati che indicano lo sviluppo di un ambiente lacustro-palustre; 2) sabbie ghiaiose e limi argillosi di pianura alluvionale; 3) ciottolami poligenici e polimodali di conoide alluvionale. In testa, si trovano i resti di un saprolite di alterazione profonda, resto preservato di un suolo che marca piccoli lembi della più alta superficie conservata nel bacino. La successione intermedia, spessa in affioramento pochi metri, comprende: 1) ciottolami monogenici ad elementi arenaceo-pelitici di valle fluviale ad indicare un drenaggio verso est, evidente anche morfologicamente; 2) limi argillosi e subordinate sabbie ghiaiose di piana alluvionale; 3) ciottolami monogenici ad elementi arenaceo-pelitici di conoide alluvionale. Su questi depositi sono presenti paleosuoli differenziati secondo la granulometria e recanti segni di cicli deposizionali minori, ma comunque molto evoluti. La successione più recente include depositi fluviali e di versante, affioranti nella valle del Torrente Zanca, attuale tributario del Fiume Bruna, e i depositi palustri della depressione stessa. La successione del Torrente Zanca indica un cambiamento nell apporto clastico; i depositi, infatti, sono costituiti interamente da clasti carbonatici derivanti dallo smantellamento del Calcare Cavernoso. La frazione grossolana delle successioni più antiche deriva invece esclusivamente dallo smantellamento delle formazioni peliticoarenacee e calcaree liguridi. La successione, spessa fino a 50 metri e terrazzata, include: 1) brecce monogeniche di versanti che definivano il fianco orientale della conca; 2) ciottolami che riempiono una prima paleovalle del Torrente Zanca; 3) ciottolami di una seconda paleovalle; 4) travertini fitoclastici spessi fino a 5 metri, indicativi di un temporaneo sbarramento della valle; 5) ciottolami di una terza paleovalle, relativa ad una fase in cui il T. Zanca era un immissario della conca formando un piccolo delta-conoide. Gli eventi geomorfico-sedimentari ipotizzabili dall architettura di queste successioni verranno discussi, pur nella presente incertezza cronologica, in relazione a possibili fenomeni tettonico-magmatici che hanno interessato l area durante il Quaternario. 9

11 PLEISTOCENE TRAVERTINES OF CENTRAL ITALY: PALEOENVIRONMENTAL RECONSTRUCTION FROM POLLEN AND STABLE ISOTOPES A. BERTINI 1, 2, A. MINISSALE 2, M. RICCI 1 and O. VASELLI 1, 2 1 Dipartimento di Scienze della Terra - Via G. La Pira 4, Firenze 2 CNR - Istituto di Geoscienze e Georisorse - Via G. La Pira 4, Firenze Combined stable isotopic compositions (δ 18 O, δ 13 C) and palynological analyses have been carried out in order to verify if travertine deposits (thermogenic travertine), as well as calcareous tufa (meteogenic travertine), can be used as a proxy for paleoclimatic reconstructions. Two Pleistocene travertines have been selected in central Italy, i.e. Serre di Rapolano (Siena) and Tivoli (Rome) whose record permits to investigate the last ca 120 kyrs. With the aim to obtain sounder paleoenvironmental inferences, the methodological approach was firstly performed in studying the Serre di Rapolano deposit. The taphonomic biases affecting the pollen assemblages were assessed by analyzing different travertine lithofacies (e.g. crystalline crust, shrub, lithoclastic), terrigenous interstrata and paleosoils. From an actively depositing small pool located in the Borro Canatoppa, near the Terme San Giovanni spring, a sample of water and the soft sediment depositing were also collected together with a musci at the pool edges. Vegetation and environmental changes were reconstructed by the fluctuations of trees, shrubs, herbs (including steppic taxa such as Artemisia) and aquatic plants. The pollen evidence allowed the recognition of local and regional events: the former marked by the development of an herbaceous vegetation typical of wetlands (i.e. marshes), the latter by the increase of steppic (especially Artemisia) or arboreal taxa (e.g. Pinus and Quercus). Isotopic analyses in selected samples, with more positive δ 18 O values in temperate periods have been evidenced. At Tivoli sixty-four samples were collected from a core 32 m thick, and analyzed for their isotopic composition. Although the paucity of the available residual dry sediment, palynological analyses were also carried out in order to provide additional paleoenvironmental clues. Despite most samples were barren, to virtually barren in palynomorphs, the chronologic frame and the calibrated pollen record from nearby studied sites (e.g. Laghi di Monticchio, Lagaccione, Valle di Castiglione) allowed a cross comparison between the two different paleoclimatic proxies (stable isotopes and pollen). The good correspondence between the environmental fluctuations at both Tivoli and Serre di Rapolano, with those described in other terrestrial deposits, ice-core, as wells as deep-sea records, demonstrates that travertine deposits, can be conveniently used to investigate the paleoclimate in the late Quaternary. 10

12 IL BACINO MIOCENICO DI RADICONDOLI NEL QUADRO DELL EVOLUZIONE NEOGENICA DELL APPENNINO SETTENTRIONALE A. BROGI 1 and D. LIOTTA 2 1 Dipartimento di Scienze della Terra, Siena University, Via Laterina 8, Siena, Italy 2 Dipartimento di Geologia e Geofisica, Bari University, Via Orabona 4, Bari, Italy Lo sviluppo dei bacini neogenici del versante tirrenico dell Appennino Settentrionale è oggetto, da circa una decina di anni, di un acceso dibattito scientifico. I bacini miocenici e pliocenici della Toscana meridionale, infatti, sono stati tradizionalmente interpretati come graben o semigraben collegati con la tettonica distensiva (Martini and Sagri, 1993) che, dal Miocene Inferiore-Medio, avrebbe interessato il settore più interno della catena (Carmignani et al., 1994). Questa ipotesi è stata contestata da alcuni autori che, diversamente, sostengono che l intero arco appenninico settentrionale sia stato interessato da un regime tettonico compressivo, attivo dal Cretacico Superiore fino al Pleistocene (Boccaletti et al., 1998). In questa presentazione vengono illustrati i risultati di uno studio realizzato in uno dei bacini miocenici più importanti della Toscana meridionale (Bacino di Radicondoli, Serravaliano sup.-messiniano sup.; Lazzarotto and Mazzanti, 1978, Martini and Sagri, 1993), preso in considerazione da alcuni autori per dimostrare che i bacini miocenici della Toscana meridionale si sono sviluppati in un regime compressivo piuttosto che distensivo. Bonini and Moratti (1995) e Bonini et al. (1994), infatti, hanno riconsiderato l assetto geologico dei depositi di riempimento del Bacino di Radicondoli ed hanno ipotizzato che questo ultimo coincida con una depressione strutturale collegata allo sviluppo di thrust miocenici. In questa ipotesi alternativa, che è stata estesa a tutti i bacini miocenicopliocenici della Toscana meridionale (Bonini et al., 2001), il versante tirrenico dell Appennino Settentrionale è considerato sottoposto a tettonica compressiva almeno fino al Pleistocene inferiore. Il nostro studio si è basato sulla riconsiderazione dell assetto strutturale dei depositi di riempimento del bacino e sull analisi dell assetto strutturale delle unità del substrato pre-neogenico. Quest ultima è stata realizzata integrando dati geologici di sottosuolo, derivati dall attività di ricerca geotermica condotta soprattutto nel margine occidentale del bacino, e nuovi dati strutturali di superficie acquisiti sia nei depositi miocenici, sia nelle unità del substrato. I risultati hanno messo in evidenza che, in accordo con Bonini and Moratti (1995) e Bonini et al. (1994), il Bacino di Radicondoli non è delimitato da faglie dirette ed è caratterizzato da una evidente sinforme che deforma i depositi di riempimento, che raggiungono uno spessore di circa 1000 metri in corrispondenza del depocentro del bacino. I depositi del Bacino di Radicondoli poggiano sempre sulle Unità Liguri più elevate della pila orogenica e sono stati interessati da deformazioni contrazionali, sindeposizionali, riconoscibili alla scala del bacino ed a quella dell affioramento. Il bacino di Radicondoli, tuttavia, come evidenziano i dati di sottosuolo, si colloca in un settore della crosta fortemente assottigliato per effetto dell attività di detachment estensionali (Bertini et al., 1991). La loro attività ha causato la segmentazione laterale di alcune Unità Liguri, della Falda Toscana e, localmente, del Gruppo del Verrucano, causando la diretta 11

13 A. BROGI and D. LIOTTA sovrapposizione delle Unità Liguri più elevate direttamente sulle rocce metamorfiche che costituiscono il basamento metamorfico toscano (Brogi et al., 2005 cum bibl.). Secondo la nostra ipotesi il Bacino di Radicondoli coincide con una depressione strutturale sinclinalica collegata con la segmentazione laterale di alcune unità del substrato. La sedimentazione è avvenuta contemporaneamente all attività dei detachment estensionali che ha portato al progressivo approfondimento del bacino, unitamente al graduale aumento dell inclinazione dei margini durante la sedimentazione. Questo processo ha permesso lo sviluppo di strutture contrazionali, come pieghe asimmetriche e faglie inverse, con vergenza verso il centro del bacino, per effetto della gravità. Nell insieme, quindi, il Bacino miocenico di Radicondoli costituisce una depressione strutturale sviluppata tra il Serravaliano superiore ed il Messiniano superiore, collegata con la tettonica estensionale che durante questo intervallo di tempo ha interessato tutto il versante tirrenico dell Appennino Settentrionale. BIBLIOGRAFIA BOCCALETTI M. and SANI F Cover thrust reactivations related to internal basement involvement during Neogene-Quaternary evolution of the Northern Apennines. Tectonics, 17, BONINI M., BOCCALETTI M., MORATTI M. and SANI, F Neogene crustal shortening and basin evolution in Tuscany (Northern Apennines). Ofioliti, 26, BONINI M., CERRINA FERONI A., MARTINELLI P., MORATTI G., VALLERI G., CERTINI L The intramessinian angular unconformity within the Radiconodoli syncline (Siena, Tuscany, Italy): structural and biostratigraphical preliminary data. Mem. Soc. Geol. It., 48, BONINI M. AND MORATTI G Evoluzione tettonica del bacino neogenico di Radicondoli-Volterra (Toscana meridionale). Boll. Soc. Geol. It., 114, CARMIGNANI L., DECANDIA F.A., FANTOZZI P.L., LAZZAROTTO A., LIOTTA D. and MECCHERI M Tertiary extensional tectonics in Tuscany (northern Apennines, Italy). Tectonophysics, 238, LAZZAROTTO A. and MAZZANTI R Geologia dell'alta Val di Cecina. Boll. Soc. Geol. It., 95, MARTINI I.P. and SAGRI M Tectono-sedimentary characteristics of Late Miocene-Quaternary extensional basins of the northern Apennines, Italy. Earth-Science Reviews, 34, BERTINI G., CAMELI G.M., COSTANTINI A., DECANDIA F.A., DI FILIPPO M., DINI I., ELTER F.M., LAZZAROTTO A., LIOTTA D., PANDELI E., SANDRELLI F. and TORO B Struttura geologica fra i monti di Campiglia e Rapolano Terme (Toscana meridionale): stato attuale delle conoscenze e problematiche. Studi Geol. Camerti, 1, BROGI A., LAZZAROTTO A., LIOTTA D., RANALLI G. and CROP 18 WORKING GROUP Crustal structures in the geothermal areas of southern Tuscany, Italy: insights from the CROP 18 deep reflection lines. J. Volc. Geoth. Res. 148,

14 UN POSSIBILE CONTRIBUTO MICROBIOLOGICO NELLA DEPOSIZIONE DI MOONMILK CALCITICO NELLA GROTTA NERA (129 A) (PENNAPIEDIMONTE-CH) P. CACCHIO 1, G. FERRINI 2, G. DI PRINZIO 1, C. ERCOLE 1, R. CONTENTO 1, M. DEL GALLO 1 and A. LEPIDI 1 1 Dpt di Biologia di Base ed App., Lab. Microbiologia, Facoltà di Scienze, Univ. degli Studi L Aquila 2 Dpt di Scienze Ambientali, Lab. Geologia, Facoltà di Scienze, Univ. degli Studi L Aquila La Grotta Nera (129A) e una peculiare forma sotterranea del sistema carsico della Montagna d Ugni (Parco della Majella - CH) nota per la sua scenografica bellezza; questa cavità deve infatti la sua fama alle numerose e ben sviluppate concrezioni costituite esclusivamente da moonmilk che molti specialisti ritengono uniche in Europa. Moonmilk e un termine generico che indica un materiale pastoso/semifluido, con contenuto in acqua variabile tra %, costituito da una sospensione di cristalli di grandezza micrometrica di calcite, idromagnesite, gesso o altri materiali. Data la variabilità composizionale del moonmilk, non stupiscono i molti meccanismi, abiotici o biotici, proposti per spiegarne la formazione; si nota però che i meccanismi biotici, in particolare riferibili ad azione microbica, nonostante siano ritenuti potenzialmente importanti siano stati, a tutt oggi, oggetto di pochi approfondimenti. Al fine di indagare un possibile ruolo dei batteri nella genesi degli speleotemi calcarei presenti nella Grotta Nera, abbiamo condotto un analisi microbiologica su due campioni di moonmilk: tale analisi ha rivelato la presenza di una microflora eterotrofa coltivabile piuttosto elevata ( x 10 4 ufc/g sostanza secca) e quindi non riconducibile ad una presenza occasionale. Il 93% degli isolati batterici e risultato in grado di precipitare CaCO 3 su terreno agarizzato contenente Ca ++. I controlli non inoculati o inoculati con cellule autoclavate sono risultati privi di precipitati cristallini. Gli isolati calcificanti presenti nel moonmilk con una abbondanza relativa più elevata, producono in vitro una maggiore quantità di cristalli. L attitudine alla precipitazione dei ceppi calcificanti, saggiata a 15, 22 e 32 C, e risultata più intensa alla temperatura di grotta, con una maggiore percentuale di cristalli lontani dalla colonia batterica, facendo presupporre l intervento di meccanismi di precipitazione diversi. Il 50 % dei batteri calcificanti ha mostrato anche attività di solubilizzazione, confermando il contributo di questo processo nella deposizione del moonmilk. Le osservazioni al SEM hanno rivelato: la natura lamellare-fibrosa del moonmilk; la presenza di cellule calcificate e non sui cristalli recuperati da piastra, l interazione di queste cellule con il substrato, di loro impronte all interno del cristallo e di un biofilm ad azione cementante. I dati microbiologici sono stati confrontati con le osservazioni geo-speleologiche che indicano, come fattore caratterizzante ed esclusivo di questa cavità, una circolazione delle masse d aria ed una relativa temperatura interna anomala (superiore di almeno 10 C al valore teorico stimabile per questa zona) ed un ridotto spessore della copertura litoide che permette scambi con l orizzonte pedogenizzato sovrastante. I risultati ottenuti forniscono indicazioni su un contributo attivo dei batteri calcificanti nella genesi delle caratteristiche concrezioni di moonmilk presenti nella Grotta Nera, la cui abbondanza può essere ricondotta al particolare microclima interno ed alla particolare conformazione dell ipogeo che assicurano un optimum di crescita microbica e, quindi, una più intensa attività di precipitazione. 13

15 FLUVIAL BARRAGE CALCAREOUS TUFA SYSTEMS AS POTENTIAL MARKERS OF QUATERNARY UPLIFT IN SOUTHERN TUSCANY: A CASE FROM THE CHIANTI HILLS E. CAPEZZUOLI 1, A. GANDIN 1, H.M. PEDLEY 2 and F. SANDRELLI 1 1 Dipartimento di Scienze della Terra, Università di Siena, Via Laterina 8, Siena 2 Department of Geography, University of Hull, Hull, HU6 7RX, U.K. Karstic springs and related calcareous deposits are sensitive ecotops to paleohydrological changes, especially in semiarid Mediterranean environments. Previous works pointed out the presence in the Chianti Hills, of some small encrusting calcareous systems, perhaps lacustrine in origin, and described as "travertine". A recent geological survey recognized at least 8 different systems existing in the surrounding area of Castellina in Chianti (Si). Petrographic, morphological and sedimentological analyses indicate that they are fluvial barrage calcareous tufa deposits. These systems (Mulino delle Spugne, Fioralle, Tregole, Tramonti, Montanino Nord, Montanino Sud, Molinuzzo, Le Ripe), partially still active, consist of one or more downstream arcuate dams of tufa that impound lake systems within gorge valleys sites. The lakes are now totally infilled by alluvial/colluvial sediments, with the upper, flat surface intensively farmed. Tufa deposition is still active along limited areas of the dams in association with small streams. The dams, with a maximum height of about 10 meters, are formed by a range of lithofacies (Phytoherm framestone, Phytoclast tufa, Phytoherm boundstone, Oncoidal and Cyanolith tufa). Characteristics common to all include the similar altitude of the upper encrusting surface (varying between the 450 m a.s.l. of Montanino and the 479 m a.s.l. of Tregole system). Karstic theory applied to these deposits suggests a common origin from the same ground water table for all. Consequently, the presence of older and fossil fluvial barrage tufa at higher elevations provides evidence of geologically older hydrological changes afecting the ground water table. These changes may provide an alternative mean of quantifying the uplift of a region. Preliminary studies in the Chianti Hills, have recognized three different areas at a similar altitude, where the local detrital deposits present morphological and lithological characteristics indicating that they are ancient back-dam tufa lakes infill sites. Confirmation of this reconstruction will be useful evidence to demonstrate uplift of this area. 14

16 TECTONIC CONTROL ON SEDIMENTARY EVOLUTION IN THE ARIANO BASIN (LOWER PLIOCENE, SOUTHERN APENNINES, ITALY) S. CIARCIA, T. MITRANO and M. TORRE Dipartimento di Scienze della Terra, Università degli Studi di Napoli Federico II, Largo S. Marcellino 10, Napoli, Italy In this paper we provide outcrop data of the Lower Pliocene deposits, connected to a tectonically active setting of Pliocene satellite basins, located in the Campania sector of the Southern Apennines chain, in Montecalvo Irpino area. The examined successions have been accumulated in the wedge-top depocenters of the Pliocene Foreland Basin System (De Celles and Giles, 1996) of the Southern Apennines. In such depocenters, during the upper part of the Lower Pliocene, a complete sedimentary cycle with very evident transgressive-regressive characters was developed. The paleoenvironmental and paleogeographic evolution of the Pliocene basins has been strongly influenced by the contemporary tectonic evolution of the chain, characterized by sindepositional compressive stress and polyphasic evolutionary history, as well-known for the contiguous Ofanto piggy-back basin (Hippolyte et al., 1994). The northern border of the Pliocene deposit outcrops is marked by a structural element of regional importance, the Benevento- Buonalbergo tectonic line (Bonardi et al., 1988; Ortolani and Pagliuca, ). This structural element corresponds to the master fault located along the northern margin of the Pliocene sedimentary basin that has a structural configuration as an halfgraben. The studied deposits are here defined Baronia Formation and ascribed to the Lower Pliocene, G. puncticulata biozone (MPl 4a, Rio et al. 1994) (Amore et al., 1998). They are well developed in Benevento and Ariano Irpino area, Baronia Mountains and Daunia Hills (Ciarcia et al., 1998; 2003; 2006). Within this unit a complete sedimentary cycle, with a total thickness that can exceed the 2000 meters in the Baronia Mountains (e.g. Trevico 1 well, AGIP Mineraria, 1961), is reconstructed. It is characterized by a finingupward succession at the bottom, followed by a coarsening-upward sequence on the top. The litostratigraphic succession is constituted by clastic deposits (clays, sands and conglomerates) of alluvial, transitional, and marine environments and it is sealed on the top by the middle Pliocene deposits or Quaternary alluvial and volcanic sediments, in unconformity. A detailed geologic survey in the Montecalvo Irpino area and a stratigraphicsedimentologic analysis of several sections allow us to recognize the physical characters of the Lower Pliocene clastic succession (fig. 1) and to reconstruct its lateral and vertical variations. The analysis of the sedimentary facies provides the main depositional mechanism that interested the Ariano Basin sediments. The studied deposits pertains to alluvial, transitional and marine environments, arranged in 6 facies associations: fluvial, lagoonal, foreshore, shoreface, deltaic and shelf (fig. 2). The data derived from the geologic survey and the analysis of exposed litostratigraphic and sedimentologic sections in the studied area, indicate a clear tectonic influence on the sedimentation. In fact, the reconstruction of the geometry of the sedimentary bodies show the presence of a sinsedimentary tectonic unconformity. Furthermore, the attitudes of deposits outcropping in the first one show deepening towards E-NE with inclination variable from degree until subhorizontal. 15

17 S. CIARCIA, T. MITRANO and M. TORRE Figure 1 Synthetic stratigraphic log of the Lower Pliocene sequence cropping out in Montecalvo Irpino area. Analogous situation is evident in the northern sector, where deposits of the same stratigraphic interval, with layers deepening towards SW, show a decreasing inclination (from 50 to 30 degrees) proceeding towards south. These data allow to characterize a suprateneuous synclines and related composite unconformity (Anadon et al., 1986), associated to folding and thrusting, occurred during the sedimentation and connected to the structuring of the orogenic prism in this sector of the Ariano Basin. During the fold growth the rapid subsidence and the high sedimentation rates due to an elevated clastic contribution from the raising southern areas causes the development of a Gilbert type delta system (Dorsey et al., 1995; Garcia-Garcia et al., 2006), that shows a progradation towards the north-east. The shell layers over the delta topset, moreover, have been interpreted in similar tectonosedimentary contexts like condensed intervals, deposited during periods with relatively reduced clastic contribution; these conditions allowed the colonization a lot of abundant and various faunal assemblage (Dorsey et al., 1995). At the same time, during the growth of the syncline a progressive deepening of the basin in the hinge area occurred, causing a slip along the south-eastern margin of the Benevento-Buonalbergo tettonic line, with transition from foreshore to shoreface facies associations and formation of a composite progressive unconformity (Anadon et al., 1986). In the Montecalvo Irpino natural section a frequent alternation of marine and non marine (coastal and lagoonal) environments are recorded and referable to a basin margin. The geographic location of the studied area make us to suppose that in the initial part of the basin activity it represented the connection area between the Arianese- Baronia depocenter (eastern portion), and the Benevento depocenter (western portion). This hypothesis is confirmed by the wide spread of shelf deposits. Fig.2 - Stratigraphic scheme showing the lateral and vertical facies associations variations in Montecalvo Irpino area. 16

18 S. CIARCIA, T. MITRANO and M. TORRE Figure 3 Paleogeographic sketch of the inner margin of Ariano Basin. After a short condition of piggy-back by-pass (sensu Ori and Friend, 1984), the deposition of clastic not marine deposits, related probably to a tectonic event, causes the final isolation of the Benevento depocenter (fig.3) and the beginning of its dismantling. REFERENCES AGIP MINERARIA, Trevico 1 well stratigraphical log. Technical report. AGIP Mineraria Servizio geologico, S. Donato Milanese. AMORE O., BASSO C., CIAMPO G., CIARCIA S., DI DONATO V., DI NOCERA S., ESPOSITO P., MATANO F., STAITI D. and TORRE M., Nuovi dati stratigrafici sul Pliocene affiorante tra il fiume Ufita ed il torrente Cervaro (Irpinia, Appennnino meridionale). Boll. Soc. Geol. It. 117, ANADON P., CABRERA L., COLOMBO F., MARZO M. and RIBA O., Syntectonic intraformational unconformities in alluvial fan deposits, eastern Ebro basin margins (NE Spain). In: Foreland Basins (Ed. by P. A. Allen and P. Homewood). Spec. Publ. Int. Ass. Sediment. 8, BONARDI G., D ARGENIO B. and PERRONE V.,1988. Carta geologica dell Appennino meridionale. Mem. Soc. Geol. It. 41, Tav. all. in scala 1: CIARCIA S., DI DONATO V., MITRANO T. and TORRE M., I depositi del bacino di Benevento (Pliocene inferiore, Appennino meridionale): nuovi vincoli stratigrafici e paleoambientali. Boll. Soc. Geol. It. 125, CIARCIA S., DI NOCERA S. and TORRE M., Sistemi di fan delta al margine orientale del Bacino di Ariano (Pliocene inferiore, appennino apulo-campano). Boll. Soc. Geol. It. 117, CIARCIA S., DI NOCERA S., MATANO F. and TORRE M., Evoluzione Tettono-sedimentaria e paleogeografica dei depocentri wedge-top nell ambito del foreland basin system pliocenico dell Appennino meridionale (settore irpino-dauno). Boll. Soc. Geol. It. 122, DE CELLES P.G. and GILES K.A., Foreland basin systems. Basin Research 8, DORSEY R.J., UMHOEFER P.J. and RENNE P.R., Rapid subsidence and stacked Gilbert-type fan deltas, Pliocene Loreto basin, Baja California Sur, Mexico. Sedimentary Geology 98, GARCIA-GARCIA F., FERNANDEZ J., VISERAS C. and SORIA J. M., Architecture and sedimentary facies evolution in a delta stack controlled by fault growth (Betic Cordillera, southern Spain, late Tortonian. Sedimentary Geology 185, HIPPOLYTE J.C., ANGELIER J., ROURE F. and CASERO P., Piggyback basin development and thrust belt evolution: structural and paleostress analyses of Plio-Quaternary basins in the Southern Apennines. J. of Struct. Geol. 16, ORI G.G. and FRIEND P.F., Sedimentary basins formed and carried piggyback on active thrust Sheets. Geology 12, ORTOLANI F. and PAGLIUCA S., Carta geologica della comunità montana Fortore Beneventano. Note illustrative ed inquadramento regionale. Boll. Soc. Natur. in Napoli 98-99, RIO D., SPROVIERI R. and RAFFI I., The Gelasian stage: a proposal of a new Chronostratigraphic Unit of the Pliocene series. Riv. It. Paleont. Strat. 100,

19 SEEP-CARBONATES AND FLUID EXPULSION PROCESSES IN THE MIOCENE OF THE NORTHERN APENNINES CONTI S., FONTANA D. and MECOZZI S. Dipartimento di Scienze della Terra, Università di Modena e Reggio Emilia In the Miocene satellite and foredeep basins of the northern Apennines, numerous carbonate bodies were identified by specific palaeoecological, sedimentological, compositional and isotopic features as products of the microbial oxidation of methanerich fluids (Conti and Fontana, 2005 and references herein). These methane-derived carbonates occur in large turbiditic bodies (Mt. Cervarola and Marnoso-arenacea Formations) and in slope hemipelagites (Vicchio and Verghereto Marls, and Ghioli di letto mudstones). Dominant rock types are calcilutitic limestones, marly limestones, calcareous marls and calcarenites. Carbonates exhibit typical 13 C- depleted signatures indicative of methane oxidation On the basis of morphological and stratigraphic features two main types of seepcarbonates were distinguished in the field (Type 1 and 2 Conti and Fontana,1999a). The type 1 is composed of a horizontal repetition of decametric to heptometric carbonate bodies, lenses and pinnacles. They have a thickness of 5-30 m and an extension that ranges from 10 m to 100 m. The basal portions of these huge bodies are strongly brecciated, made up of intraformational polygenic breccias and rarely extraformational. The Sasso Streghe (Modena Apennines) and Monte Petra (Romagna Apennines) carbonate outcrops are excellent examples of this type of seep-carbonates. The type 2 is made of numerous marly-calcareous lenses, irregular column-like bodies with a dimension ranging from some decimetres to 3 4 m and a thickness of cm to 3 m. Carbonate bodies are aligned along bedding strikes, or horizontally and vertically scattered and not related to a precise stratigraphic level. Many of them consist of several lenticular units vertically stacked and separated by thin pelitic levels, thus suggesting periodic growth. The Vicchio outcrops (Tuscan Apennines) are representative of this second type of carbonates. Carbon isotope measurements show that carbonates from type 1 and 2 are typically depleted in 13 C but the amount of depletion seem to differ between them. Therefore seepcarbonates type 1 appear significantly depleted in δ 13 C (-30/-55) while seep-carbonates type 2 are only moderately depleted (-10/-20). Our presentation will draw attention to the distinctive characters of the two types of chemoherms, In particular we discuss geometry, isotope geochemistry and brecciation, in context with the composition and origin of carbon rich fluids, the flux discharge and rate, and with the mechanisms of expulsion (diffused or focused). Possible relationships with gas hydrate destabilization processes are also discussed. 18

20 STRATIGRAPHY AND TECTONICS OF THE NEOGENE-QUATERNARY MINOR BASINS OF THE INNER NORTHERN APENNINES: THE TAFONE BASIN (ROMANI MTS., SOUTHERN TUSCANY-NORTHERN LATIUM) G. CORNAMUSINI 1-2, F. BONCIANI 1, I. CALLEGARI 1, P. CONTI 1-2, L.M. FORESI 2 and G. MASSA 1 1 Centro di Geotecnologie, Università degli Studi di Siena, Via Vetri Vecchi, San Giovanni V.no (AR) 2 Dipartimento di Scienze della Terra, Università degli Studi di Siena, Via Laterina, Siena Introduction The inner part of the Northern Apennines has been interested, since Middle Miocene, by a post-collisional crustal extension, that led to the formation of subsident sedimentary basins. The physiographic, structural and depositional features have been linked with tectonic activity, developed with various modalities during Middle Miocene-Pleistocene. In the present work we have examined these features for the Tafone Valley in the Romani Mts. (Southern Tuscany Northern Lazio), with particular focusing to the Miocene succession (Fig. 1). It has been collected structural and litostratigraphic data based on field work, from petrographic analyses of Miocene coarse deposits (conglomerates and sandstones), from micropaleontological and biostratigraphic analyses, from sedimentological analyses. We have moreover examined mining surveys data, now available in the internet in the DBGM (GeoMinerario DataBase) of the Tuscany Region. The main aim of this work, beyond supplying a geologic framework of the area, is to characterize the Tafone Basin from the palaeogeographic point of view, its depositional and structural evolution, and its organization in the system of the Neogene-Quaternary sedimentary basins Fig. 1 Geological sketch-map of the Tafone Valley of the hinterland of the Northern Apennines. 19

21 CORNAMUSINI G., BONCIANI F., CALLEGARI I., CONTI P., FORESI L.M. and MASSA G. The Tafone Basin constitutes an element of peculiar geologic interest. It represents one of the southernmost Neogene-Quaternary basins of the northern apenninic back-arc area, connected with the Tarquinia Basin. Another point of interest is tied to the peculiar geological framework of such basin, with particular emphasis to the locally folded Miocene succession. We then discuss the relationships among Middle Miocene deposits and the younger sedimentary successions, their organization in the basin and the meaning inside the geodynamic context of the chain. Geological Setting and Stratigraphy The Tafone Basin is lengthened in NNW-SSE (Apennine direction) and delimited from normal faults that develop a graben structure. The present stratigraphic-structural succession of the area is made of strongly thinned stack of tectonic units, that represents the remaining of the Apenninic orogenic wedge in this area. Above this last, through high angle stratigraphic unconformity, the neoautochthonous sequence is present; it is subdivided in several successions: Miocene succession, Pliocene succession and Pleistocene succession, separated by angular unconformities. There are moreover, scatter residual outcrops of volcanic cover, derived from the pyroclastic activity of the Vulsini Mts.. More in detail, the remaining structural stack of the area is the result of the accretionary processes and of the subsequent strong tectonic elision ( serie ridotta Auctt.). It is constituted from the bottom by: the Monticiano-Roccastrada Unit of late Paleozoic-Triassic age, outcropping here with the Poggio al Carpino Sandstones Formation, the Verrucano Formation and the Tocchi Formation; the Tuscan Nappe, represented here by the Cavernoso Limestone (Late Triassic) and by the youngest formation, which is the Macigno Sandstones (Late Oligocene-Early Miocene); the Ligurian Units, represented here by the S. Fiora-Morello Unit, constituted by the S. Fiora and the Pietraforte formations (Late Cretaceous). The Neogene successions, in particular the Middle Miocene sediments (Manciano Sandstones of Poggio Sanopie), or the Upper Miocene sediments (Tafone valley), lie unconformably onto Ligurian Units only. The Upper Miocene succession is overlied, through angular unconformities, by the marine succession Early Pliocene on age, or by alluvial Pleistocene sediments. The Miocene succession has been the main object of our investigations. The Upper Miocene succession has been subdivided in two lithostratigraphic units: the Poggio il Forno Conglomerates (PFC), of continental/transitional environment, and the Botro dell Acqua Bianca Clays (BAC), of shallow marine/lagoonal environment. Facies analyses show transition from fluvial-delta apparatus to fan-delta apparatus and then to lagoon and shallow sea-water environments; the fluctuating of the sea level, was connected with tectonic-eustatic processes. The composition of pebbles and sandstones of the continental lower unit (PFC), and of the upper marine-marginal environment unit (BAC), is indicative of the dismantling of limestone-arenaceous covers (Ligurian Units). The Miocene sediments are limited by two main high-angle normal faults of the Tafone basin, while the Pleistocene alluvial deposits are more strongly controlled by the structural depression of the Tafone Basin. Differently from Miocene deposits, the Pleistocene ones derive from the dismantling of the Metamorphic Unit and they are environmentally interpreted as relative to the interaction between a fluvial system and transversal-basin alluvial-fan systems. 20

22 CORNAMUSINI G., BONCIANI F., CALLEGARI I., CONTI P., FORESI L.M. and MASSA G. The Miocene deposits show tectonic structures linked to the post-collisional extensional tectonics, of Plio-Pleistocene age, as normal faults forming graben. An interesting peculiarity of the Miocene succession is the deformative structures like folds, locally with overturned limbs, that affect the eastern part of the basin, close to the masterfault. Discussion and regional considerations The geological features of the Tafone Basin find strong analogies with other similar Neogene basins of the southern Tuscany. They are so indicative of the regional evolutive setting of the Northern Apennines back-arc area. In particular, the Tafone Basin showed, during late Miocene, close connections with the Tarquinia Basin, rather with the northernmore Albegna Basin, from which it was separated by an east-west ridge (Argentario-Manciano ridge), to develop a different environmental and sedimentary history. 21 Fig. 2 - Scheme of the tectonicdepositional evolution of the Tafone Basin. a- middle Miocene marine shallow basins of the serie ridotta ; b- late Miocene-early Pliocene continental to lagoonal to marine basin; c- Pleistocene alluvial basin. The tectonic-sedimentary evolution model proposed here is the following (Fig. 2). During the Middle Miocene, the extensional phase of the socalled serie ridotta determined the development of morphologicalstructural depressions, where the Ligurian Units are directly in contact with the Calcare cavernoso Fm. or with the metamorphic formations of the Monticiano-Roccastrada Unit; the structural position of these last is over the flat, interposed among the megaboudins. Such depressions correspond with the shallow-water depositional basin of the Manciano Sandstones. This model allows to consider the Middle Miocene deposits as the first depositional occurrence of the post-collisional extensional phase in the inner part of the Apennine chain. So, they

23 CORNAMUSINI G., BONCIANI F., CALLEGARI I., CONTI P., FORESI L.M. and MASSA G. represent the first neoautocthonous cycle. During the late Miocene, the basin suffered further subsidence due to the development of medium-high angle normal faults, to form a like-graben structure of continental to marine-lagoonal environment. The upper Miocene sediments had sources and drainage coming from the ridge located to east, where Ligurian Units were outcropping. During the Plio-Pleistocene the Tafone graben increased too, until to reach the present conformation. The uplift of the ridges increased too, in particular that located to east (Monte Bellino Ridge), as far as reach the total dismantled of the Ligurian Units and the subaerial exposure of the metamorphic rocks of the Monticiano-Roccastrada Unit. Inside the basin, alluvial fan systems developed, interacting with the fluvial system. The alluvial fans were fed by the eastern ridge, showing a metamorphic composition of the clasts, emphasizing an unroofing sequence for the whole neoautochthonous succession. Furhtermore, during the Pliocene-Early Pleistocene uplift, the Miocene succession near the Roccaccia master fault, has been deformed with the development of western facing folds with vertical and overturned bedding. Their genesis could be connected with tectonic-gravitational processes related with the activity of the high angle normal faults, and not with compressional tectonic regime. Similar features, recognized also for other Neogene basins of the southern Tuscany (e.g. Bacino del Casino in Lazzarotto and Sandrelli, 1977; Bacino di S. Barbara in Lazzarotto and Liotta, 1991; Bacino di Radicondoli in Bonini and Moratti, 1995), allow therefore to indicate for such structures an extensional context. After all, the Tafone Basin represents a clear and representative example of the development of the whole Apennines backarc basin system. REFERENCES BONINI M. AND MORATTI G Evoluzione tettonica del bacino neogenico di Radicondoli-Volterra (Toscana meridionale). Boll. Soc. Geol. It., 114, LAZZAROTTO A. AND LIOTTA D Structural features of the Lignitiferous Basin of Santa Barbara, Upper Valdarno area. Boll. Soc. Geol. It., 110 (3-4), LAZZAROTTO A. AND SANDRELLI F Stratigrafia e assetto tettonico delle formazioni neogeniche nel Bacino del Casino (Siena). Boll. Soc. Geol. It., 96 (5-6),

24 STRATIGRAFIA E MODELLIZZAZIONE 3-D DI UN BACINO CONTINENTALE INTERMONTANO: IL BACINO PLIOCENICO DI SANTA BARBARA (VALDARNO SUPERIORE, TOSCANA) G. CORNAMUSINI 1-2, A. IELPI 2, I. CALLEGARI 2, F. BONCIANI 2, E. GUASTALDI 2 and A. TONINI 2 1 Dipartimento di Scienze della Terra, Università di Siena 2 Centro di Geotecnologie, Università di Siena Il Bacino di Santa Barbara è parte del Bacino plio-quaternario del Valdarno Superiore, di cui rappresenta la prima fase di sviluppo tettono-sedimentario. Esso appartiene al sistema dei bacini intermontani-interni neogenico-quaternari dell Appennino Settentrionale. Il Bacino del Valdarno Superiore, caratterizzato da depositi continentali di età variabile dal Pliocene medio al Pleistocene, ha un orientazione appenninica NNO- SSE, ed è delimitato ad ovest dai Monti del Chianti e ad est dai Monti del Pratomagno. Il Bacino di Santa Barbara, ne contraddistingue il settore occidentale, caratterizzato da depositi continentali di età Pliocene medio-superiore. Numerosi sono gli studi che riguardano l organizzazione stratigrafica dei depositi di questo ultimo (Azzaroli and Lazzeri, 1977; Sagri, 1991; Lazzarotto and Liotta, 1991; Albianelli et al., 1995; 1997; Ghinassi and Magi, 2004; Ghinassi et al., 2004, Coltorti et al., 2007), i quali sono basati sostanzialmente su aspetti di carattere stratigrafico/sedimentologico. I vari Autori hanno evidenziato tre principali fasi tettono-deposizionali per il Bacino del Valdarno Superiore, che hanno condotto alla formazione di una successione sedimentaria continentale suddivisa in unità stratigrafiche separate da superfici di discordanza. Una prima fase deposizionale, che interessa il Bacino di Santa Barbara, del Pliocene medio-superiore, una seconda fase del Pliocene sommitale-pleistocene inferiore che segna l ampliamento al Bacino del Valdarno Superiore ed una terza fase del Pleistocene medio. I caratteri del bacino sono stati riferiti ad un sistema di tipo semigraben impostatosi in un contesto estensionale (Martini and Sagri, 1993), mentre altri Autori (Bonini, 1999), riferiscono, in particolare il Bacino di Santa Barbara, ad un contesto compressivo. In questo lavoro, a seguito di un rilevamento geologico di dettaglio, viene rivista la stratigrafia del Bacino di Santa Barbara ed inserita in un sistema di modellizzazione tridimensionale con applicazioni geostatistiche, utilizzando oltre ai dati di campagna, dati minerari relativi all attività estrattiva dei giacimenti di lignite. La modellizzazione 3-D ha consento una migliore visualizzazione ed interpretazione della distribuzione dei corpi e delle rispettive geometrie, oltre al tracciamento delle superfici geologiche nel bacino, ed i loro rapporti con le strutture deformative. Sulla base dei dati geologici di campagna e dei dati minerari, è stato così possibile ricostruire un quadro dello sviluppo, dell architettura e dell evoluzione stratigrafico-strutturale del Bacino di S. Barbara, attraverso una prospettiva di modellizzazione tridimensionale. Quadro geologico e Stratigrafia Il Bacino di S. Barbara si configura come un bacino di carattere estensionale, anche se probabilmente si è strutturato in una fase di pre-rift, che a partire dal Pliocene medio ha interessato questo settore della catena. Più nel dettaglio, il Bacino di Santa Barbara è caratterizzato dai depositi del primo sintema del Bacino del Valdarno Superiore (Sintema di Castelnuovo), sui quali poggiano in discordanza stratigrafica angolare i depositi del secondo sintema (Sintema di Montevarchi) e del terzo sintema (Sintema di Monticello- 23

25 CORNAMUSINI G., IELPI A., CALLEGARI I., BONCIANI F., GUASTALDI E. and TONINI A. Ciuffenna). I depositi del Sintema di Castelnuovo sono organizzati in una successione di ambiente continentale, di età riferibile al Pliocene medio-superiore. L organizzazione stratigrafica di tale sintema è data dal basso dai Ciottolami e sabbie di Spedalino, riferibili ad apparati di conoide alluvionale/delta conoide lacustre (Gilbert delta), che appoggiano sul substrato, dato dal Macigno e da termini liguri strutturati in un potente livello olistostromico. I Ciottolami e sabbie di Spedalino mostrano passaggi lateroverticali alle Argille di Meleto, le quali sono caratterizzate alla base da un potente livello sabbioso (spessore circa 20 metri). Le Argille di Meleto passano poi in alto alle Sabbie di San Donato, le quali a loro volta sono delimitate alla sommità da una superficie di troncatura erosiva. I Ciottolami e sabbie di Spedalino sono formati da conglomerati monogenici e fortemente eterometrici, con abbondante matrice sabbiosa, i cui ciottoli derivano esclusivamente dalla Formazione del Macigno. Essi formano due apparati di conoide parzialmente distinti e coalescenti, poggianti sulla suddetta formazione in forte discordanza angolare, con direzione di distribuzione dei sedimenti circa est-ovest e con la parte apicale nel settore occidentale. I conglomerati passano latero-verticalmente a sabbie e poi alle Argille di Meleto, denotando un senso di trasporto dei paleoflussi da ovest verso est. La conoide più meridionale (collocata tra Castelnuovo dei Sabbioni e Neri) ha una distribuzione dei ciottoli e delle facies con aumento della distalità da SSO verso NNE, mentre la conoide più settentrionale (San Donato in Avane) sembra avere una distribuzione da OSO verso ENE. I Ciottolami e sabbie di Spedalino sono delimitati in alto da un livello di sabbie massive contenenti abbondanti elementi carboniosi, con passaggio graduale ad argille grigie ed argille lignitifere (Argille di Meleto), le quali assumono uno spessore massimo di circa 150 metri nell area depocentrale. Nella parte bassa di tale unità sono inoltre presenti dei livelli di lignite, di cui due principali, oggetto dell escavazione mineraria, evidenziano cospicui resti organici, con tronchi di albero anche in posizione di crescita. Le argille, di ambiente lacustre/palustre, passano poi in alto, tramite un contatto concordante e graduale, a sedimenti prevalentemente sabbiosi e sabbioso-limosi (Sabbie di San Donato) massivi o con laminazione incrociata, contenenti abbondanti resti vegetali, da riferire ad un ambiente di delta-conoide, ad alimentazione dai settori occidentali, che passa verso l alto ad un sistema fluvio-deltizio. Nelle Sabbie di San Donato ricorrono inoltre, livelli di microconglomerati poligenici e di argille grigie, oltre ad orizzonti di paleosuoli. Inoltre, poco ad est di Meleto, al di sopra delle Sabbie di San Donato, sono presenti sabbie ben cernite di colore chiaro riferibili alla cosiddetta Rena Bianca, che Ghinassi et al. (2004), hanno recentemente riferito alla parte basale del Sintema di Montevarchi. Sui depositi del Sintema di Castelnuovo e sul substrato poggiano ancora in discordanza angolare i depositi prevalentemente conglomeratici, sia del Sintema di Montevarchi, sia del Sintema di Monticello-Ciuffenna. In particolare, sono presenti depositi correlabili con i Ciottolami e sabbie di Caposelvi, affioranti nel settore settentrionale del bacino, dati prevalentemente da conglomerati eterometrici in abbondante matrice sabbiosa, riferibili a sistemi di delta-conoide a provenienza occidentale. I ciottoli sono dati quasi esclusivamente dallo smantellamento delle arenarie del Macigno, con locali concentrazioni di ciottoli di gneiss, di granito e calcarei. Questi denotano lo smantellamento di un livello caotico (debris flow), intercalato alle arenarie del Macigno, affiorante sul versante orientale dei Monti del Chianti (vedi in Cornamusini 24

26 CORNAMUSINI G., IELPI A., CALLEGARI I., BONCIANI F., GUASTALDI E. and TONINI A. et alii, questo volume). Questo ulteriore aspetto facilita la ricostruzione dell apparato di conoide, il quale doveva avere una distribuzione dei paleoflussi da SSO verso NNE. Dal punto di vista della tettonica, il Bacino di S. Barbara è delimitato a sud all altezza di Cavriglia ed a nord (Gaville), da faglie antiappenniniche (faglie trascorrentitranstensive), ad ovest dal versante chiantigiano in cui si osservano rapporti stratigrafici di onlap e faglie dirette appenniniche (faglia del Vignale) che ribassano verso oriente; ad est all interno del bacino si riconosce l alto strutturale di Meleto, delimitato da faglie dirette (faglia di Meleto), individuando la depressione principale nell area di Bomba. Inoltre, nel settore meridionale (area di Castelnuovo dei Sabbioni), si evidenzia che la paleomorfologia del bacino doveva essere molto articolata ed irregolare, come mostrano anche frequenti rapporti di onlap. Le giaciture a medio-elevata inclinazione (fino a 55 ) individuate nei livelli basali del Sintema di Castelnuovo, in prossimità del sistema di faglie dirette del Vignale, trovano secondo noi giustificazione, sia nell azione di trascinamento dell attività di faglia, sia nelle paleomorfologie, escludendo quindi genesi legate alla formazione di strutture plicative legate ad un regime tettonico compressivo. Modello 3-D Sulla base dei dati minerari ENEL (circa 850 stratigrafie di pozzo) e dei dati ottenuti durante il rilevamento di campagna, è stato generato un modello geologico tridimensionale (Fig. 1) che visualizza la struttura e l architettura stratigrafica del bacino e del relativo riempimento sedimentario. L area investigata dal modello si estende dal margine occidentale del bacino, dove affiora il substrato pre-pliocenico, sino al limite orientale di affioramento dei depositi del Sintema di Castelnuovo, dove questi sono ricoperti dai sedimenti del Sintema di Montevarchi. Figura 1 Bozza del modello tridimensionale del bacino. A-livello del substrato bacinale; B- livello Ciottolami di Spedalino; C e D- in grigio scuro base e tetto del livello lignitifero inferiore; E e F- in grigio scuro base e tetto del livello lignitifero superiore. cs conoide di Spedalino; fsd faglia del Vignale; fb faglia di Bomba. 25

27 CORNAMUSINI G., IELPI A., CALLEGARI I., BONCIANI F., GUASTALDI E. and TONINI A. Il modello stratigrafico è stato creato tramite il software Geovariances ISATIS attraverso fasi sequenziali: dopo una prima analisi statistica descrittiva dei dati di pozzo, si è provveduto ad un analisi geostatistica, al fine di evidenziare le correlazioni spaziali e di creare quindi, dall analisi dei semivariogrammi sperimentali, modelli che permettessero una soddisfacente modellazione. Infine, attraverso algoritimi di kriging e co-kriging, sono state generate una serie di superfici relative ai vari contatti tra le associazioni di litofacies all interno del bacino. Il modello stratigrafico è stato poi importato nell ambiente software gocad dove è stato integrato con le superfici che rappresentano le faglie individuate nell area, ricostruite a partire dai dati di superficie, e dal modello digitale del terreno (DEM), ricostruito a partire dai dati topografici. Il modello geologico completo ha permesso così di visualizzare le varie superfici e corpi deposizionali, quali le geometrie e morfologie della base del bacino, del tetto della conoide dei Ciottolami e sabbie di Spedalino dei livelli di lignite intercalati alle Argille di Meleto e del tetto di queste ultime, delle Sabbie di San Donato, oltre alle strutture tettoniche. Sono così state bene evidenziate le paleomorfologie del fondo del bacino (superficie del bedrock), caratterizzato da una morfologia irregolare ed articolata, caratterizzata da più zone depocentrali, delimitate ad ovest dalla faglia bordiera del Vignale. Dall interpretazione dei dati emersi, sembra che quest ultima sia stata attiva anche durante la deposizione dei depositi del Sintema di Castelnuovo, nell ambito dei quali le modeste strutture plicative presenti in prossimità della suddetta faglia, sono probabilmente riconducibili ad effetti di trascinamento. Il bacino risulta così essere caratterizzato da una base piuttosto articolata, con la parte settentrionale più regolare, mentre la parte meridionale, sembra essere maggiormente irregolare e profonda. L analisi delle superfici, integrata con i dati di rilevamento di campagna, ha poi permesso di migliorare l interpretazione delle strutture deformative e la disposizione e geometrie dei depositi di riempimento. L analisi dei dati tridimensionali, ha altresì permesso di meglio visualizzare il sistema sino a ricavare informazioni di maggiore dettaglio sui depocentri deposizionali, sugli spessori dei depositi, sull architettura e sull attivita tettonica sinsedimentaria. In definitiva, il modello 3-D ad alta risoluzione si propone come strumento per la determinazione della distribuzione e dei volumi dei corpi geologici rappresentati, aspetto fondamentale per la comprensione dell estensione degli stessi nel sottosuolo e del relativo utilizzo come risorsa. BIBLIOGRAFIA ALBIANELLI A., BERTINI A., MAGI M., NAPOLEONE G. AND SAGRI M Il bacino plio-pleistocenico del Valdarno Superiore: eventi deposizionali, paleomagnetici e paleoclimatici. Il Quaternario, 8 (1), AZZAROLI A. AND LAZZERI L I laghi del Valdarno superiore. Centro Studi Geologia Appennino CNR, Università di Firenze, Pubbl. 26, 4pp. BONINI M Basement-controlled Neogene polyphase cover thrusting and basin development along the Chianti Mountains ridge (Northern Apennines, Italy). Geol. Mag. 135, COLTORTI M., RAVANI S. AND VERRAZZANI F The growth of the Chianti Ridge: progressive unconformities and depositional sequences in the S. Barbara Basin (Upper Valdarno, Italy). Il Quaternario, 20 (1),

28 CORNAMUSINI G., IELPI A., CALLEGARI I., BONCIANI F., GUASTALDI E. and TONINI A. GHINASSI M. AND MAGI M Variazioni climatiche, tettoniche e sedimentazione al passaggio Pliocene Medio-Pliocene Superiore nel bacino del Valdarno Superiore (Appennino Settentrionale). Boll. Soc. Geol. It., 123, GHINASSI M., MAGI M., SAGRI M. AND SINGER S. B Arid climate 2.5 Ma in the Plio-Pleistocene Valdarno Basin (Northern Apennines, Italy). Palaeogeography, Palaeoclimatology, Palaeoecology, 207, LAZZAROTTO L. AND LIOTTA D Structural features of the lignitiferous basin of Santa Barbara, Upper Valdarno area. Boll. Soc. Geol. It., 110, MARTINI I.P. AND SAGRI M Tectono sedimentary characteristics of Late Miocene-Quaternary extensional basin of Northern Apennines, Italy. Earth Sci. Rev., 34,

29 I DEPOSITI DI AVANFOSSA DEL SETTORE ORIENTALE DEI MONTI DEL CHIANTI (FORMAZIONE DEL MACIGNO): NUOVI DATI STRATIGRAFICI E COMPOSIZIONALI G. CORNAMUSINI 1-2, A. IELPI 2, I. CALLEGARI 2 and F. SANDRELLI 1 1 Dipartimento di Scienze della Terra, Università di Siena 2 Centro di Geotecnologie, Università di Siena Il Macigno dei Monti del Chianti rappresenta il principale riempimento torbiditico dell avanfossa nordappenninica al passaggio Oligocene-Miocene. Esso poggia in concordanza stratigrafica su alternanze argillitico-calcaree della Scaglia toscana. Lo spessore complessivo del Macigno dell area, è indicato nella letteratura in circa metri, comprendente anche potenti intercalazioni di Liguridi (tre quelle principali), interpretate da molti autori come olistostromi. In questa nota sono riportati i risultati preliminari di uno studio sedimentologico-petrografico sul Macigno affiorante sul versante orientale dei Monti del Chianti. Nel complesso il Macigno di questo settore è dato da una successione arenacea silicoclastica, con un rapporto A/P>>1, a cui si intercalano livelli pelitici ed un potente e lenticolare livello olistostromico, dato da materiale calcareo-argillitico ad assetto caotico, derivante perlopiù dalla Formazione di Canetolo. Il Macigno di quest area è costituito in prevalenza da facies arenacee grossolane, organizzate in strati spessi e molto spessi, massivi ed amalgamati, o più raramente gradati. Tali facies ed associazioni di facies di conoide sottomarina, sono da ricondurre ad apparati di lobo molto prossimali ed alla transizione lobo-canale. Ricorrono anche livelli fortemente lenticolari, spessi alcune decine di metri, di arenarie molto grossolane e microruditi in strati massivi amalgamati, interpretabili come riempimenti di canale. Associati ai livelli grossolani e presenti alla base, ed in particolare al tetto dell olistostroma, vi sono facies pelitico-arenacee, date da siltiti, argilliti ed arenarie fini, talvolta marne (Marne di San Polo), interpretabili come depositi da sottoalimentazione su alti morfologici. Inoltre, nei pressi di Casa Cimpetto, affiora un livello spesso circa 15 metri dato da un conglomerato matrice-sostenuto ad elementi eterometrici ad alto grado di arrotondamento e medio-bassa sfericità, a matrice sabbioso-pelitica. I ciottoli, di dimensioni variabili da pochi cm a 20 cm, sono dati da litotipi cristallini, in particolare gneiss e rocce granitoidi, con subordinati calcari a nummuliti, oltre a clasti di dimensioni maggiori ed a maggiore angolosità di arenarie riconducibili al Macigno. Un livello simile, con cui si ritiene correlabile, affiora più a nord, nell area di Cintoia-Monte Scalari, a circa 200 metri dalla base formazionale. La porzione di successione di Macigno stratigraficamente posta al di sopra dell olistostroma, evidenzia facies più evolute sottocorrente, con strati torbiditici meno spessi e con granulometrie minori, con maggiore organizzazione interna e strutture sedimentarie, ed un complessivo rapporto A/P>1. Dal punto di vista composizionale, le arenarie (arcose ed arcose litiche) sono piuttosto omogenee per tutta la successione indagata. Il contenuto in carbonati (bioclasti e litoclasti) è modestissimo. Mentre riguardo la frazione litica, questa è caratterizzata per gran parte da litici metamorfici (gneiss, micascisti, filladi, ecc.) e da basso contenuto in litici vulcanici (inferiore al 15% della frazione litica) e sedimentari; si è però osservato che nelle facies arenaceo-ciottolose (con diffusi clasti fuori taglia) il contenuto in litici 28

30 CORNAMUSINI G., IELPI A., CALLEGARI I. and SANDRELLI F. vulcanici è lievemente maggiore. A più livelli stratigrafici ricorrono poi strati arenacei grossolani caratterizzati da una petrofacies contraddistinta da un forte contenuto in carbonati (arenarie ibride/miste), quali bioclasti, intraclasti e litoclasti, e presenza tra i litici non carbonatici di frammenti metamorfici, vulcanici e di serpentinite. Questi strati sembrano perlopiù associati a livelli particolari, come quelli presenti al top dell olistostroma, oppure alla base del livello a debris flow. Nel complesso i dati sedimentologici e stratigrafici, indicano un sistema torbiditico a bassa efficienza di trasporto, in cui si riconoscono associazioni di facies di transizione lobo-canale, o di lobo molto prossimale. Il livello conglomeratico caotico, ha le caratteristiche di un tipico processo di debris flow coesivo, in cui vengono coinvolte anche porzioni di successione arenacea. I depositi pelitici presenti alla base ed al tetto dell olistostroma, indicano fasi di sottoalimentazione o addirittura di sedimentazione emipelagica con le marne, che precedono e che soprattutto seguono la messa in posto della frana di materiale ligure, il cui corpo doveva dare luogo ad un cospicuo rilievo morfologico nel bacino. Tale quadro sembra essere quindi in accordo con un bacino di avanfossa allungato in senso NO-SE ed asimmetrico, con il cuneo orogenico dato da Unità Liguri accavallate sulla scarpata interna, che doveva dare luogo a potenti fenomeni di dissesto gravitativo sottomarino, a formare corpi olistostromici. Un elemento di discussione viene invece introdotto dai caratteri sedimentologico-composizionali della successione arenacea. Difatti, il carattere prossimale e di bassa efficienza del sistema torbiditico, male si accorda con una provenienza dei flussi torbiditici da settori remoti delle Alpi occidentali, come gran parte della letteratura indica per il Macigno del Chianti. In aggiunta, il livello a debris flow, denota comunque, sia per i caratteri sedimentologico-idrodinamici, sia per i caratteri composizionali, una provenienza occidentale al bacino, quale potrebbe essere dal Massiccio sardo-corso. E pertanto plausibile l ipotesi, meritevole di ulteriori indagini, che il complessivo sistema di drenaggio clastico dell avanfossa al passaggio oligomiocene, possa essere individuato nei settori occidentali del sistema di avanfossa, in bacini meno profondi collocati sulle unità orogeniche in accavallamento, e che davano luogo a più conoidi torbiditiche a bassa efficienza, con più punti di immissione nell avanfossa e conseguente deflessione delle torbide in senso longitudinale, tipico dei bacini confinati, come verificato da alcuni Autori per il Macigno costiero. 29

31 AGE OF THE UPPERMOST PALEOSHORELINES IN THE MIDDLE TIBER VALLEY D. COSENTINO 1, P. CIPOLLARI 1, G. FUBELLI 1 and E. GLIOZZI 1,2 1 Dipartimento di Scienze Geologiche - Università Roma Tre L.go San L. Murialdo, 1, I Roma 2 IGAG-Istituto di Geologia Ambientale e Geoingegneria, Via Bolognola, 7, I Roma In the southern part of the Middle Valley of the Tiber River (MVT) field and analytical data have been recently collected for the new Italian geological mapping project (CARG, scale 1:50,000; sheets 357-Cittaducale and 366-Palombara Sabina). In particular, the uppermost paleoshorelines (UPS) and their related marine and transitional deposits have been mapped and analysed between the Fara in Sabina Mts and the western Lucretili Mts. In the southern part of the MVT, the present elevation of the UPS decreases from a maximum height of 270 m a.s.l. (West of Fara in Sabina Mts) up to a minimum value of 170 m a.s.l. (Castel Chiodato). In this area, a series of independent biochronological and biostratigraphical data point to a Late Pliocene age for the UPS. This chronological indication comes from the following stratigraphic sections, which are close or in correspondence to the UPS: 1) Bocchignano-Castel S. Pietro; 2) Torre Baccelli; 3) Stazzano; 4) Castel Chiodato; and 5) Molino del Moro. 1) Bocchignano-Castel S. Pietro This section, which consists of sands, marls, clays and some lignitiferous horizons, cuts across the uppermost part of the basin fill of the Rieti intramontane basin. It is heteropic with the Chiani-Tevere Fm. very close to its uppermost paleodepositional surface. This surface, which is recognizable as far as Rieti, defines the alluvial plain of the Paleofarfa River and correlates the sea level markers of the UPS from the west (270 m a.s.l.). It is recognized along the western side of the Fara in Sabina Mts. From lignitiferous deposits of the Bocchignano-Castel S. Pietro area, remains of Anancus arvernensis and Stephanorhinus etruscus were collected (Tuccimei, 1889, 1891; Maxia, 1949). Taking into account the biochronology of the large mammals of the Italian Peninsula (Gliozzi et al., 1997), A. arvernensis and S. etruscus coexisted during the Middle Villafranchian mammal age, characterizing the Montopoli, St. Vallier and Costa S. Giacomo faunal units (Late Pliocene). 2) Torre Baccelli This section represents a delta-plain palaeoenvironment and is located very close to the UPS at the western side of the Fara in Sabina Mts (270 m a.s.l.). This section consists mainly of fine-grained deposits with fresh-water and terrestrial gastropods (Valvata cristata, Lymnaea sp., and Carychium sp.) intercalated with brackish-water horizons containing Hydrobia sp., Potamides sp. and Bittium reticulatum (BARISONE et al., in press). The uppermost samples of the Torre Baccelli section provided one molar tooth of Apodemus cf. A. atavus and an abundant pollen record characterized by Taxodiaceae, Symplocos, Nissa, Hamamelis and Distylium (Barisone et al., in press). According to Pontini and Bertini (2000), the last occurrence of Symplocos, Nyssa and the Hamamelidaceae were Late Pliocene in central Italy. 30

32 D. COSENTINO, P. CIPOLLARI, G. FUBELLI and E. GLIOZZI 3) Stazzano This section shows some sea level markers related to three different paleoshorelines. These are distributed between 261 m and 277 m a.s.l., and represented three highfrequency transgressive-regressive cycles during the last long-term transgressive event, which defines the UPS of the MTV in the area. The Stazzano section shows three Lithophaga lithophaga pierced horizons ( m, 268 m and 277 m a.s.l.), associated with short-term basinward and landward facies migration. Above the L. lithophaga pierced horizon at 268 m a.s.l., gastropod-bearing black sandy silts (Hydrobia (Peringia) ulvae, H.(P) acuta, Mohrensternia angulata, Potamides tricinctus, Hynia prismatica, Thericium cf. T. vulgatum, Bittium cf. B. reticulatum) with benthic foraminifers (Ammonia parkinsoniana, A. tepida, A. beccarii, Elphidium crispum, E. granosum) and ostracods (Cyprideis torosa) define a brackish environment (coastal lagoon) characterized by changes in paleosalinity. Despite one specimen that has just been found, the occurrence of Mohrensternia angulata could be of biochronological interest. According to Malatesta (1974), the distribution of M. angulata encompasses the Miocene-Pliocene interval. In Italy, two specimens of M. angulata have been collected from the Pliocene strata of S. Faustino (Umbria) (Malatesta, 1974). 4) Castel Chiodato The uppermost portion of this section represents the paleodepositional surface (170 m a.s.l.) related to the UPS of the MVT. Fine-grained deposits with fresh-water ostracods characterize the basal portion of the Castel Chiodato section, which is defined by an upper delta-plain environment with shallow fresh-water lakes. A coarsening-upward trend characterizes the middle-upper portion of the section, where Amphistegina-bearing sand layers have been found at the top. 5) Molino del Moro This section is characterized by cliff breccias passing to fining-basinward conglomerates, with well-rounded pebbles in a carbonate matrix yielding Amphistegina spp., rhodoliths, bryozoa, etc. The Molino del Moro section represents the coastal deposits of the UPS (170 m a.s.l.) of the MVT. In central Italy two Amphistegina levels have been found in Pliocene strata (Di Bella et al., 2005). The youngest of these levels (Gelasian) also occurs in the MVT (Tenaglie- Fosso San Martino Unit; Mancini et al., 2004). According to these independent biochronological and biostratigraphical data, the UPS in the southern part of the MVT should be Gelasian instead of Santernian as recently reported by Mancini et al. (2007). The occurrence of Amphistegina spp. within the UPS coastal sediments suggests a deposition during the last warm oscillation before the strong Late Pliocene climatic deterioration (2.1 Ma) (Di Bella et al., 2005). REFERENCES BARISONE G., ESU D., GLIOZZI E., KOTSAKIS T., PONTINI M.R., in press. Inquadramento biocronologico e paleoambientale dei depositi plio-pleistocenici. In: COSENTINO et al., in press. Note illustrative della Carta Geologica d Italia alla scala 1:50.000, Foglio 357-Cittaducale. Appendice I,

33 D. COSENTINO, P. CIPOLLARI, G. FUBELLI and E. GLIOZZI DI BELLA L., CARBONI M.G., PIGNATTI J., Paleoclimatic significance of the Pliocene Amphistegina levels from the Tyrrhenian margin of Central Italy. Bollettino della Società Paleontologica Italiana 44, GLIOZZI E., ABBAZZI L., ARGENTI P., AZZAROLI A., CALOI L., CAPASSO BARBATO L., DI STEFANO G., ESU D., FICARELLI G., GIROTTI O., et al., Biochronology of selected Mammals, Molluscs and Ostracods from the Pliocene to the Late Pleistocene in Italy. The State of the art. Rivista Italiana di Paleontologia e Stratigrafia 103, MALATESTA A., Malacofauna pliocenica umbra. Memorie per servire alla descrizione della carta geologica d Italia 13, 487 pp. MANCINI M., GIROTTI O., CAVINATO G.P., Il Pliocene e il Quaternario della media valle del Tevere (Appennino centrale). Geologica Romana 37, MANCINI M., D ANASTASIO E., BARBIERI M., DE MARTINI P.M., Geomorphological, paleontological and 87 Sr/ 86 Sr isotope analyses of early Pleistocene paleoshorelines to define the uplift of Central Apennines (Italy). Quaternary Research 67, MAXIA C., Resti di Mammiferi rinvenuti nella miniera di lignite di San Pietro (Sabina). La Ricerca Scientifica 19, PONTINI M.R., BERTINI A., Late Pliocene vegetation and climate in central Italy: high resolution pollen analysis from the Fosso Bianco section (Tiberino Basin). Geobios 33, TUCCIMEI G., Il Villafranchiano nelle valli sabine e i suoi fossili caratteristici. Bollettino Società Geologica Italiana 8, TUCCIMEI G., Alcuni mammiferi fossili delle provincie Umbra e Romana. Memorie Pontificia Accademia Nuovi Lincei 7,

34 GENERAL FRAME AND DEVELOPMENT OF THE LATE CARBONIFEROUS TO EARLY MIDDLE TRIASSIC CONTINENTAL BASINS OF SARDINIA L.G. COSTAMAGNA and S. BARCA Dipartimento di Scienze della Terra, Via Trentino 51, Cagliari (Italy) The stratigraphic and sedimentological features of the Late Carboniferous to early Middle Triassic continental basins of Sardinia (Cassinis et al., 2000) have been described and considered along with their tectonic traits. Three different basin types have been distinguished: early Molassic, Molassic and early Alpine basins, each one of them featured by very typical sedimentary characteristics and linked to a distinct depositional cycle. The early Molassic basins (Late Carboniferous- early Early Permian), probably stretched and narrow in shape and related to transtensive-transpressive tectonics, were filled up by the dark, "limnic", coarse to fine siliciclastic, rarely carbonate successions till to 350 m thick under a warm-humid climate. The depositional environment was related to closed, fan-delta to alluvial, locally lacustrine systems. Otherwise the Molassic (late Early Permian - pre-late Permian) and the Early Alpine (late Early Triassic - early Middle Triassic) basins are generally open, very wide and featured by coarse to fine siliciclastic, alluvial red beds facies under hot, arid to subarid conditions. Nevertheless, the Molassic and the early Alpine basins successions clearly differentiated each other in thickness (at least 350 to 400 m for the Molassic basins, not more than 25 m for the early Alpine ones) and several sedimentological features (e.g. evaporites presence in the early Alpine basins). From the stratigraphic point of view, they are respectively referred to the Rotliegendes and to the Buntsandstein European facies group. Their depositional context relates almost to the whole alluvial spectrum, from the arid alluvial fan through the alluvial plain till to the coastal plain, locally represented by mudflats. Local climate evolution was due mostly to the morphotectonic evolution of the chain. Volcanics are diffuse in the first and second depositional cycle, while they are completely absent in the third one. A general model regarding the development and the sedimentary features of these extensional basins is proposed framing these basins into three tectodepositional cycles and considering all the possible implied variables ruling the products of the sedimentation, including tectonics, paleomorphology and paleoclimate. REFERENCES CASSINIS G., CORTESOGNO L., GAGGERO L., PITTAU P., RONCHI A. and SARRIA E. (2000) Intern. Field Conf. on the continental Permian of the Southern Alps and Sardinia (Italy). Regional reports and general correlations. Brescia, Sept. 1999, 116 pgs. 33

35 FACIES ANALISYS AND PALEOENVIRONMENTS OF THE LOWER PERMIAN MOLASSIC PERDASDEFOGU BASIN (E SARDINIA) L.G. COSTAMAGNA 1 and A. RONCHI 2 1 Dipartimento di Scienze della Terra, Via Trentino 51, Cagliari, Italy 2 Dipartimento di Scienze della Terra, Via Ferrata 1, Pavia, Italy Sedimentological and paleoenvironmental studies on the continental Lower Permian Rio su Luda Fm. (Perdasdefogu Basin: Cassinis et al., 2000) are in progress. Several stratigraphic sections have been characterized, with particular regards to lacustrine carbonate lithofacies, in order to relate facies development and basin evolution. The stratigraphic profiles evidence the following plain trasgressive-regressive sequence: 1. At the base, unconformably over the Paleozoic Basement, the Permian succession starts with polygenic conglomerates mainly related to debris flows, probably accumulated along alluvial fan slopes; 2. Lately, given a rate of tectonic subsidence bigger than sedimentation rate, a rapid enlargement and deepening of the intramontane basin triggers the retreat of the alluvial fans. This led to deposition in the middle to central part of the basin of an alluvial-tolacustrine terrigenous, fining upwards sequence. Here, thinly laminated siltites, clayey siltites, sandstones and rare conglomerates occur, showing evidence of deeper environments (lacustrine inundites and turbidites) comprised between lake shoreline and offshore. Repeated volcaniclastic intercalations evidence a strong tectono-magmatic influence; 3. Afterwards, the subsidence slows down and is overwhelmed by the sediment supply: the basin starts to be gradually filled up by both limited terrigenous inputs and indigenous sedimentation. The depth progressively shallows, leading to the developing of a lacustrine carbonate sequence, represented by (outer?) slope to shore deposits. This sequence is initially characterized by alternations of micritic, thinly laminated, dark carbonate pelites, pelites and clayey limestones (bioclastic mudstones) with scattered pyrite nodules, suggesting temporarily anoxia episodes. Then, regular alternations of laminated pelites and limestones follow, topped by more or less silicified dolomites, dolomitic limestones, limestones and cherts overprinting carbonate deposits. These carbonates are related to stromatolitic boundstones and bioclastic to oncolitic, rarely ooidal packstones/grainstones. Stromatolitic fenestral fabric suggests periodical variations of shoreline position. More rarely, former likely evaporitic nodules, to-date completely silicified are associated to the boundstones. Episodic, coarse to fine, siliciclastic-epiclastic horizons are also interspaced among the carbonate layers. Embedded into the carbonates, discontinuous coal layers related to marsh settings, repeatedly interdigitate with the coastal lake environment. This sequence is related to slope to coastal and bench-beach environments, far from terrigenous inputs and prograding over the offshore. Locally, at the top of the sequence, sandstones and quartzose, poorly-organized conglomerates seems to lie conformably over the carbonates, and could represent the prograding, alluvial filling-up of the basin in response to a further uplift phase. More frequently, Lower Permian volcanic products cover finally the carbonates: in turn they are unconformably overlain by the Jurassic succession. 34

36 L.G. COSTAMAGNA and A. RONCHI REFERENCES CASSINIS G., CORTESOGNO L., GAGGERO L., PITTAU P., RONCHI A. and SARRIA E., Intern. Field Conf. on the continental Permian of the Southern Alps and Sardinia (Italy). Regional reports and general correlations. Brescia, Sept. 1999, 116 pgs. 35

37 APPLYING THE PEDOSTRATIGRAPHIC LEVEL CONCEPT TO GEOLOGICAL MAPPING E.A.C. COSTANTINI and R. NAPOLI Istituto Sperimentale per lo Studio e la Difesa del Suolo, Firenze, Italy Adding soil and paleosol information to geological mapping has always been a challenge for both paleopedologists and geologists (Morrison, 1993). The North American Commission on Stratigraphic Nomenclature (1983) has defined the concept and application of pedostratigraphic unit as a buried, traceable, three-dimensional body of rock that consists of one or more differentiated pedologic horizons (Art. 55a). The upper and lower boundaries of a pedostratigraphic unit are related to the soil horizons formed by pedogenesis in a buried soil profile. A pedostratigraphic unit is characterized by the range of physical and chemical properties in the type area, rather than by typical properties exhibited in a type section. Consequently, a pedostratigraphic unit is identified on the basis of a composite stratotype (Arts. 8d and 57b). The concept of pedostratigraphic unit has also been utilized in Italy, especially at the detailed scale (Cremaschi, 1978; Amorosi, 1996), but also at the regional scale (Preti, 1999). More recently, in the project new geological map of Italy at 1:50,000 scale, the concept of Unconformity-Bounded Stratigraphic Units (UBSU) has been used to merge results of pedological and geological surveys (Carnicelli et al., 2003). In Italy, the geological maps usually describe the Quaternary sediments as alluvial or eluvial-colluvial and Terra Rossa deposits, sometimes subdivided according to their particle size. The maps report neither chronological distinctions nor thickness of the deposits. To improve the geological map in terms of chronology and thickness of the Quaternary deposits, it is possible to use the information coming from the study of soils and paleosols. A new concept, that of pedostratigraphic level, was worked out (Costantini et al., 2007) based on the concept of pedostratigraphic unit, for non buried soils. The rationale is that the whole soil body, from the soil surface downwards, can be classified in levels according to genetic characteristics and weathering. Therefore, a pedostratigraphic level (PL) is considered a characteristic assemblage of genetic soil horizons, formed by materials having the same degree of weathering and an estimated age through correlation to benchmark soils. The PL approach needs the characterization of profile horizons according to two criteria: the expression of pedofeatures, leading to the identification of a class of genetic horizon, and the degree of weathering of the parent material. Although both expression of pedofeatures and degree of weathering are the results of the interplay between the same soil forming factors, the first one gives better clues to determine processes often related to specific climatic or morphological conditions, whereas the amount of the weathering products of the primary materials is more related to the duration of pedogenesis. In addition, the decoupling of the two criteria allows to clearly separate pedofeatures formed in fresh or pre-weathered materials. 36

38 Horizo n Depth cm CEC/100 g clay E.A.C. COSTANTINI and R. NAPOLI Profile 7; location: Molli; 580 m (a.s.l.); land use: grassland with chestnut trees; physiography: structural surface with in filled dolines. Classification: Typic Paleudalf, fine (Soil Taxonomy); Chromi-Haplic Luvisol (WRB). A 2Bt 0-21 cm; 10YR 5/4, moist; structure: weakly fine and medium subangular blocky and strong medium granular; consistence: very friable; abrupt smooth boundary to cm; 2.5YR 4/6, moist; prominent few fine mottles and streaks (7.5YR 5/8 and 7.5YR 8/4); structure: strong fine and medium prismatic; consistence: friable; few fine and very fine manganese nodules; many iron and clay films, common manganese films; diffuse smooth boundary to 2Btd cm; 5YR 5/6, moist; prominent common fine and medium mottles and streaks (7.5YR 5/8 and 7.5YR 8/4); structure: weakly medium prismatic; consistence: firm (dense materials >60% of volume); common manganese, iron and clay films; diffuse smooth boundary to 2Btd cm; 5YR 3/4, moist; prominent common fine and medium mottles and streaks (7.5YR 5/8 and 7.5YR 8/4); massive; consistence: firm; common manganese, iron and clay films; diffuse smooth boundary to 2BCd cm; 5YR 3/4, moist; massive; consistence: firm; common manganese films; diffuse smooth boundary to 3BCd cm; 5YR 3/4, moist; massive; firm. Analytical Data silt/cla Extractable Fe g/kg y (Fed- Feo)/Fet Kaolinite (% of clay) Fed Feo Fetot A Bt Btd Btd BCd BCd Figure 1 - Example of soil profiles and pedostratigraphic correlations: PL1 - Holocene soil horizons formed on fresh sediments; PL2 - Holocene soil horizons formed on older sediments; PL3 - Late-middle Pleistocene soil horizons formed on sediments of the same age or older 37

39 E.A.C. COSTANTINI and R. NAPOLI Pedostratigraphic levels can be generated from a Soil Information System, where digital soil maps and soil attributes are stored. The information coming from the map of Pedostratigraphiuc levels can be used to generate geological maps where Quaternary deposits are divided according to their estimated age (early, middle and late Pleistocene, and Holocene), thickness, and morphological position. Figure 2 Example of geological map with subdivision of the Quaternary deposits REFERENCES AMOROSI A., FARINA M., SEVERI P., PRETI D., CAPORALE L. and DI DIO G Genetically related alluvial deposits across active fault zones: an example of alluvial fan-terrace correlation from the upper Quaternary of the southern Po Basin, Italy. [online] (verified March 2004) CARNICELLI S., CAPORALE L., MARCHI N., IASIO C., FERRARI G.A., GUERMANDI M. and TAROCCO P Paleosoils of the Apenninic margin. Pre congress field trip. 4 th European Congress on Regional Geoscientific Cartography and Information Systems. Regione Emilia-Romagna, Bologna, Italy, 39 p. 38

40 E.A.C. COSTANTINI and R. NAPOLI COSTANTINI E.A.C., NAPOLI R. and D EGIDIO G Adding information about soils and paleosols to geological maps, through the application of the pedostratigraphic level concept. Quaternary International, doi: /j.quaint CREMASCHI M., Unità litostratigrafiche e pedostratigrafiche dei terreni quaternari pedeappenninici; loess e paleosuoli tra il fiume Taro e il torrente Sillaro. Geografia Fisica e Dinamica del Quaternario 1, p NORTH AMERICAN COMMISSION ON STRATIGRAPHIC NOMENCLATURE North American Stratigraphic Code. The American Association of Petroleum Geologists Bulletin 67, Number 5, p MORRISON R.B How Can The Treatment of Pedostratigraphic Units in the North American Stratigraphic Code be Improved? [online] (verified March 2004). PRETI D Geological map of the Emilia-Romagna plain. Regione Emilia-Romagna, Bologna, Italy, scale 1: , 1 sheet. 39

41 CONFINED TURBIDITE SYSTEMS: THE CASE OF THE EASTERN SARDINIAN MARGIN G. DALLA VALLE, F. GAMBERI and M. MARANI ISMAR, Sezione Isituto Geologia Marina INTRODUCTION In the last thirty years, the study of modern deep water turbidite systems, with very detailed high-quality bathymetric and seismic data sets, has generated an abundant literature that has revealed the complex morphology of deep sea channels and related fans. It is generally accepted that sediment supply, regional basin tectonics and sea level variations are the main controlling factors on the deep-sea sedimentation (Weimer, 2005). The inter-relationships between these controls lead to a very large numbers of possible scenarios for the development of depositional systems. Although it is very difficult to discern the individual contribution each control had on the development of turbidite systems, recent investigations on many continental margins and on ancient sequence have highlighted that tectonics influences almost all aspects of submarine fan architecture (Reading and Richards, 1994). In particular, the size, the geometry and the morphology of the receiving basin play a fundamental role in controlling the architecture of deep-sea depositional systems (Lomas and Joseph, 2004). In this work we furnish a detailed morphological and subsurface interpretation of small turbidite systems located in sub-confined intraslope basins along the upper sector of the eastern Sardinian margin (Tyrrhenian Sea), in order to highlight the variability of overall architercture of the systems and their large scale architectural elements. DEPOSITIONAL SYSTEM OF THE EASTERN SARDINIAN MARGIN Three intraslope basins (Olbia, Baronie, nothern Ogliastra basin) have been investigated. The Olbia basin is the northernmost basin of Sardinian margin, and is bounded seaward by the Etruschi and Baronie seamounts. The Caprera fan is the main turbidite system and is composed of feeding canyons incised in the continental slope and of a wide leveed channel at the base of the slope that is a unique case in the entire eastern Sardinian margin. The Caprera fan faces a wide shelf sector, and this could explain the peculiar sedimentary architecture of its deep-sea fan. The Olbia intraslope basin is completely filled, and has developed a bypass sector to a new base level in the distal rim of the margin where the bounding seamounts die out. The effects of the lowering of the base level is evident in the distal part of the Caprera turbidite system with the development of distributary channels and of wide, low relief V-shaped erosional features. The Baronie basin is the central basin of the eastern Sardinian, and is bounded seaward by the Baronie seamount, with a lateral escape pathway represented by the Gonone-Orosei canyon system. The Posada is the main turbidite system of the Baronie basin, consisting of a deeply incised canyon in the shelf and in the slope, a small, radial fan at the base of slope and a distal distibutary channels network. The lateral bounding slope of the Baronie seamount has forced the system to change the direction of the Posada fan, from an eastward to a southward trend. Furthermore, the Posada deep sea fan is affected by large scale mass wasting processes that contribute to the reorganization of the turbidite system. 40

42 G. DALLA VALLE, F. GAMBERI and M. MARANI The Ogliastra basin is located to the south with respect the Baronie basin, and is bounded seaward by the Quirra High. The northern continental slope of the basin is characterized by slope canyons that evidence hybrid depositional characters, with multiple stages of incision, abandonment and re-incision. The Arbatax system is the main turbidite system of the nothern Ogliastra basin, showing a well developed canyon-slope channel indented on the continental slope. At the base of the slope the system develops a radial fan with an active southern sector dominated by a fan channel, and an abandoned northern sector that is the loci of intense seafloor instability and mass wasting processes. CONCLUSION The analysis of the deep sea turbidite systems of the eastern Sardinian margin has put in evidence as, also in this small and relative young passive margin, the growth patterns of the fans reflect a very complex interplay between external and internal control factors, that give rise to a wide spectrum of fan types, such that no single, all-purpose fan model can be used for describe their variability in morphology, facies and sandbody geometry. Multibeam and seismic interpretation has revealed as each turbidite systems of the margin shows strong differences its fundamental building blocks and large scale architectural elements, that do not conform to the simple deep sea fan models still used as facies prediction tools for hydrocarbon exploration and exploitation. REFERENCES LOMAS S.A. and JOSEPH P. (eds.), Confined turbidite systems. Geol. Soc., Spec. Publ., 222, Geological Society of London Special Publication, pp READING H.G. amd RICHARDS M., Turbidite systems in deep-water basin margins classified by grain-size and feeder system. American Association of Petroleum Geologists Bullettin 78, WEIMER P. and SLATT R.M The Petroleum Systems of Deep-Water Settings: SEG Distinguished Instructor Short Course Notes, pp

43 ALLUVIAL PLAIN STRATIGRAPHY AND THE VOLTURNO RIVER DYNAMICS NEAR CAPUA (CASERTA) M. DE FALCO, D. RUBERTI and M. VIGLIOTTI Dipartimento di Scienze Ambientali, Seconda Università di Napoli, Via Vivaldi, Caserta The geologic architecture of the northeastern region of the Campania Plain have been defined on the basis of numerous data. Mainly alluvial and volcanic lithofacies associations have been recognized, related to the Volturno River and Phlegrean Field activities respectively. Data have been stored in a MS Access geodatabase and managed into a GIS project, based on a numerical cartography. A three-dimensional digital terrain model (DTM) was constructed so as to allow detailed morphological analyses of the plain. In order to better evidence the morphological surface on which recent alluvial deposits accumulated, and in the attempt to correlate such a surface with the present morphological setting, it has been realized a Digital Surface Model (DSM) by fitting the depth values of each geologic unit from the database, using a multilayer grid that integrates the surfaces (top and bottom) of the various geological formations (DSM). The depth of the lithofacies deposited above the Campania Grey Tuff (CGT) have been recognized through queries in the GIS project. These depths have been interpolated with the kriging method. The resulted surface represents the paleomorphology on which, after the CGT deposition, deposits from minor eruptions and alluvial sediments deposited, controlling the present day morphology. It has been highlighted that the CGT lithofacies strongly design a depressed morphology round the Volturno River, while they crop out in the piedmont area; another deep NE-SW depression has been outlined in the deposits younger than the CGT. The study has been integrated with geomorphologic analyses, conducted on historical documents, using GIS technologies. All the acquired information, elaborated with a threedimensional graphic, have been compared with morphologic characteristics of the area, past and present, obtained from cartographic multitemporal relieves, that allow a precise reconstruction of the main river course from 1830 to the present. These informations find a direct correspondence with the areal distribution of the alluvial facies in the subsoil. In particular, by comparison with the DTM, we noted that: - A morphologically lowered area still exists in correspondence of main depression recognized on the basis of facies analysis. This leads to the assumption that it rapresents an area not completely filled, into which the Volturno River wanders. - The overlay of the abandoned meanders, deduced from the analysis of historical maps, confirms that they are all confined into the depressed area. These observations suggest that, following the deposition of the CGT, the area has undergone an active tectonics, responsible for the formation of structural lineaments that have conditioned the wandering of the Volturno River and the alluvial and volcanic deposition. The inferred structural control is confirmed by observations made in other sectors of the Campania Plain. 42

44 SEDIMENTOLOGY AND BIOSTRATIGRAPHY OF THE LOWER-MIDDLE PLEISTOCENE SEDIMENTARY SUCCESSION OF THE IONIAN PELORITANI MTS (NE SICILY) A. DI STEFANO 1 and S. LONGHITANO 2 1 Università degli Studi di Catania, Dipartimento di Scienze Geologiche, Corso Italia 57, 95129, Catania, Italy 2 Università degli Studi della Basilicata, Dipartimento di Scienze Geologiche, Campus di Macchia Romana, 85100, Potenza, Italy Calcarenitic-dominated Pleistocene successions crop out discontinuously along the Ionian flank of the Peloritani Mountains, in northeast Sicily. These sedimentary sequences record the polyphasic evolution of the western margin of the Ionian Basin during the last million of years, with the deposition of coastal systems characterized by high-gradient palaeo-bottom profiles and consequent abrupt facies transitions. Sedimentation takes place on normal fault-controlled steep ramp-type shelves, probably influenced by early-middle Pleistocene climatic optimum, that favoured the production of abundant bioclasts. The sedimentary bioclastic assemblages are predominantly formed by molluscs, foraminifera, plus echinoids, bryozoans, ostracods, barnacles, corals and red algae, indicating foramol-type association. Along the observed sections, variously scattered on the north-eastern side of the Peloritani Mts, biocalcarenites are in fact the most diffused lithotype, characterized by a suite of sedimentary facies, all referable to coastal settings. During the sedimentation, fault-driven differential coastal uplift have acted as main factor of control on the sedimentation, producing two 3 rd -order depositional sequences. They, characterized by similar stratigraphic features and for this reason considered in the past as isochronous stratal units, partially correspond to the depositional sequences detected on the Tyrrhenian margin for the same time span. The uppermost middle Pleistocene sequence recognized in the study area presents tide-dominated association of sedimentary structures that probably record the first stage of the opening of the adjacent present Messina Straits. 43

45 NON-CLASSICAL TURBIDITES IN THE MACIGNO FORMATION : THE ARENARIE ZONATE DEPOSITS (RIOMAGGIORE, LA SPEZIA, ITALY) F. FIDOLINI 1, M. GHINASSI 2 and M. PAPINI 1 1 Dipartimento di Scienze della Terra, Università degli Studi di Firenze 2 Dipartimento di Geoscienze, Università degli Studi di Padova The Macigno Formation was deposited in the Northern Apennines foredeep during the Late Oligocene-Early Miocene. In the western promontory of the La Spezia Gulf an 800 m thick pelitic-arenaceous lithofacies of the Macigno Formation ( Arenarie Zonate ) crops out. The Arenarie Zonate have been studied in the type locality of Riomaggiore, where they consist of turbiditic lobe deposits. Two groups of beds have been recognised (type A and B) from the background clayey-marly sedimentation. The first group (35% of the beds) consists of two sub-groups (A1-2). The type A1 beds ( cm) are erosively based and show a subtle lensoid geometry. The T a interval is normal graded (from coarse to medium sandstone) and contains rounded to angular mud clasts. The transition from T a to the overlying intervals is marked by an abrupt granulometric decrease. The T b interval occurs within 50% of the beds. The T c interval is always present and consists of convolute and ripple cross lamination. The T d interval is rare, whereas the T e is common. The type A2 beds (20-50 cm) are tabular and normal graded (from medium to fine sandstone). The basal surface is sharp but not erosive. These beds consist of incomplete T c-e or T b-e sequences. The most developed interval is the T c. The second group consists of two sub-groups (B1-2). The type B1 beds (5 to 30 cm thick) are tabular in geometry. The grain size ranges between siltstone to fine sandstone. These beds show complex changes in the vertical distribution of sediment grain size, although a normal or reverse grading at the bed scale have been rarely recognised. The beds are characterised by repeated internal granulometric variations, locally associated with changes in the sedimentary structures. Truncation surfaces can occur at the top of reverse graded intervals. The type B2 deposits form composite units, up to 60 cm thick, consisting of mudstone and very fine sandstone intervals. The sandstone intervals (0.3-5 cm) are sharp based and bear ripple or plane parallel laminations. The mudstone intervals (1-10 cm) are massive or plane parallel laminated. The A1 and A2 deposits are respectively referred to high- and low-density flows, associated with surge type turbidity currents and referred to the classical Bouma-type turbidites. The B1 and B2 beds are considered non-classical turbidites produced by pulsating sustained flows fed by riverine floods. The B1 type beds were probably produced during the main discharge events. The changes in flood energy are recorded by the repeated internal granulometric variations. The reverse graded intervals with the overlying erosive surface are thought to represent respectively the waxing stage and the peak of isolated events. The B2 type beds developed during the minor flood events according to their grain size and reduced thickness. 44

46 GEOLOGY AND STRATIGRAPHY OF THE PIANOSA ISLAND L.M. FORESI Dipartimento di Scienze della Terra, Università di Siena The island of Pianosa belongs to the Tuscany Archipelago; it has an extension of 10 km 2, the shoreline spreads out for 18 km, and its max altitude is 29 m a.s.l. This island is a small emerged portion of a submarine ridge, which divides the Tyrrhenian basin into two parts: the first is located between the ridge and the island of Corsica, and reaches a depth of 800 m; the second is situated between the ridge and the continent, reaching a maximum depth of 400 m. Marina del Marchese Formation and Golfo della Botte Formation are the oldest deposits of the island, and date back to the Miocene. The former is of Burdigalian age and it is characterized by outer-shelf turbiditic marly clays, outcropping with a thickness of about 150 m; the latter is characterized by 300 m of sandy clays and, in the upper part, by conglomerates, which were deposited at first in a lacustrine environment and, afterwards, into a coastal marine one. Golfo della Botte Formation unconformably lies over Marina del Marchese Formation. A stratigraphic hiatus divides the two units, thus causing the lack of the upper Burdigalian-lower Tortonian interval. Pianosa Formation overlies both the two Miocene formations, with a marked angular unconformity. This formation consists of about 30 m of biocalcarenite, characterized by sub-horizontal to distinctly clinostratified layers. It is rich in fossils, especially mollusks and algae, but there are also bryozoans, echinoids, rest of crustaceans and fishes, which testify an inner-shelf marine deposition. Pianosa Formation consists of two sedimentary units: the lower one of Piacenzian age and the upper one of upper Gelasian - Lower Pleistocene? age. Therefore, this area also experienced the Middle Pliocene uplift, recognized in the Tyrrhenian sector of the Northern Apennine. The last phase of marine deposition is represented by shell beds ( Panchina ) of Tyrrhenian age. These deposits lie horizontally on Pianosa Formation. They are rich in fossils, especially mollusks; among them, Conus testudinarius, Strombus bubonius and Patella ferruginea are recognized. Deposits younger than those of Tyrrhenian age outcrop along wide sectors of the coast and testify a continental deposition. They consist of sands embedded in a clayeymarly matrix with breccias or, sometimes, paleosoils at the base. These deposits are related to the last glacial period and often lie over the Tyrrhenian sediments and protect them from sub-aerial erosion. At present, they are partly submerged and often inclined, as the slope is. Heterometric and monogenic breccias are common along the coast, forming close to isolated small rocky promontories. They are made of elements up to 2 m in size, embedded in a reddish sandy-marly matrix. The matrix contains rare bone fragments and several shells of pulmonate gastropods, commonly belonging to the genus Helix. Those breccias represent instantaneous deposition due to the collapse of carsic caves. Others deposits are characterized by fillings of coves and cavities. They are reddish sandy-clayey sediments, which commonly contain rests of vertebrates, pulmonate gastropods and, sometimes, lithics and bone industries of Neolithic period. At present, the deposition on the island is due only to sporadic colluvial processes. 45

47 THE IMPACT OF SOURCE AREA, SHELF WIDTH, BASIN GRADIENT AND BASE LEVEL VARIABILITY ON DEEP SEA DEPOSITION (GIOIA BASIN, SOUTHEASTERN TYRRHENIAN SEA) F. GAMBERI and M. MARANI Istituto di Scienze Marine, Consiglio Nazionale delle Ricerche, Sezione Geologia Marina, Via Gobetti 101, Bologna, Italy The intraslope, Northern Gioia Basin, located in the southeastern Tyrrhenian Sea, is 50 km long and 20 km wide, and reaches a depth of about 1300 m. The Gioia/Mesima Channel/Canyon system crosses the basin. Multibeam bathymetry, seafloor reflectivity data and airgun seismic lines enlighten the recent sedimentary evolution of the basin. Along the Calabrian margin, where the shelf is absent, a coarse grained depositional system contrasts with the sediment starved setting of the Sicilian margin where the shelf is 5 km wide. A direct hyperpycnal discharge is assumed to be responsible for the input of coarse grained sediments to the Calabrian portion of the margin. Sediment discharge from relatively large rivers is focused within canyons that head in the coastal region and function as bypass conduits for sediments to be deposited in leveed channels at the base of slope. On the contrary, discharge from smaller, closely spaced rivers results in a depositional slope setting consisting of a channelized funnel-shaped depression; flows become more strongly depositional at the base of slope where a tongue-shaped lobe is deposited. The nature of the different components of the Gioia/Mesima Channel/Canyon system highlights the importance of local variations of basin gradient and temporal changes of base level in controlling submarine channel evolution. Breaks in slope cause the shift from straight to meandering channel patterns and also result in channel deactivation and overbank deposition that is prevalent from flows exiting the first meander bends along channel courses. The shape and character of the resultant splay deposits depend on the grain size of the flows that can exit the channels. The deepening of base level, causing an upslope migration of erosional processes, is responsible for the entrenchment of straight channel segments below the level of a former meandering channel. 46

48 PETROLOGICAL INVESTIGATIONS ON TRAVERTINES AND CALCAREOUS TUFA IN SOUTHERN TUSCANY A. GANDIN Dip. Scienze della Terra, Università di Siena, Via Laterina 8, Siena Terrestrial limestones are known to form in different subaerial settings such as karstic cave systems or along fluvial valleys and near cool water springs or at the emergence of thermal springs. Flowing carbonate-rich waters derived from groundwaters mostly of meteoric provenance but with different circulation/recharge history give rise to carbonate deposits respectively known as Speleothems, Calcareous tufa and Travertines The calcareous deposits formed in these different setting appear to show specific lithologic features reflecting the physico-chemical conditions of the depositing fluids, and although lithofacies and petrographic features of Speleothems and Calcareous tufa are sufficiently known, those of Travertines still need a definite characterization and classification. Calcareous tufa are massive porous beds containing frequent remains of invertebrates and macrophytes. They are made up of dominantly micritic calcite of biotic and abiotic precipitation, forming stromatolitic, phytohermal or phytoclastic facies. The depositional fluvial/palustrine system is fed by carbonate-rich waters mostly deriving from karstic springs or in some cases from diluted and cooled, originally thermal waters. The carbonate deposition that mainly derives from biologic (photosynthetic) and mechanic (vaporization/evaporation) removal of CO 2 from flowing or standing waters, results to be controlled by the availability of meteoric water and thus by climatic conditions. Travertines are well bedded, often finely laminated compact limestones, composed in the proximal part of the thermal system by peculiar crystalline crusts and in the distal part by bacterial/cyanobacterial laminites often associated with calcified-bubble facies and paper-thin rafts. In this system the carbonate deposition mainly derives from intense degassing of the emerging waters consequent to the rapid drop in temperature of the waters flowing along the drainage network. Their mineral content originates in deep geothermal/hydrothermal conditions where hot waters charged with HCO 3 - of meteoric and hypogean derivation, are able to dissolve high quantities of carbonate and/or evaporitic bedrock. The circulation of hot waters, allowed by open fractures/faults is ultimately controlled by extensional tectonics. The critical elaboration and comparison of the petrofacies of deposits related to the three main genetic groups of terrestrial carbonates and in particular of the lithofacies of Calcareous Tufa and Travertines that are still connected with the parent water and source systems, will provide criteria for their univocal lithologic identification so that the mainly climate-controlled Calcareous Tufa and the mainly tectonics-controlled Travertines can be correctly detected even on the field. 47

49 THE LATE PLEISTOCENE SEDIMENTARY RECORD FROM THE ROMITO CAVE ARCHAEOLOGICAL SITE (CALABRIA, ITALY) M. GHINASSI 1, A.C. COLONESE 2, Z. DI GIUSEPPE 2, L. GOVONI 3, D. LO VETRO 2, G. MALAVASI 3, F. MARTINI 2, S. RICCIARDI 4 and B. SALA 3 1 Dipartimento di Geoscienze, Università degli Studi di Padova 2 Dipartimento di Scienze dell Antichità G. Pasquali, Università degli Studi di Firenze 3 Dipartimento di Biologia ed Evoluzione, Università degli Studi di Ferrara 4 Centro di Ricerche Archeobotaniche - Archeoflorae, Dipartimento di Archeologia, Università degli Studi di Bologna The Romito Cave opens in the Lao River valley, at 275 m above the sea level and about 25 km from the Tyrrhenian coast of Calabria. Archaeological excavations revealed a succession spanning from the Gravettian to the Late Epigravettian culture (Late Pleistocene). The present study is focused in the lower part (about 2.5 m thick) of the cave fill succession, where three main sedimentary units have been identified (RM1-3). Each unit consists of karts alluvial sediments capped by anthropogenic deposits. The RM1 alluvial deposits (50 cm thick) point to confined and persistent flows generating wellstratified bars and feeding crevasse splays during the major flood events. The 10 cm thick anthropogenic deposit at the top of interval RM1 represents the first significant episode of human settling within the cave. The alluvial and anthropogenic deposits of unit RM2 are respectively 90 cm and 50 cm thick. The alluvial RM2 interval was emplaced by shortlived and weakly-confined flows. These deposits testifies a decrease of watercourses competence, culminating in the first episode of drainage deactivation, that was, in turn, followed by an enduring phase of human settling. The RM3 alluvial deposits (70 cm thick) attests the drainage re-establishment and gradual transition from low-competence watercourses to persistent streams. The abrupt occurrence of few meters thick anthropogenic deposits above the RM3 unit suggests a second episode of drainage deactivation, and the final decline of water sediment transport within the cave. Radiocarbon data highlight that the first decrease in drainage competence (units RM1-2; Kyr BP) fits with the instauration of regional dry climatic conditions during the last glacial maximum. The wetting trend following this dry stage is documented by the re-establishment of underwater drainage, and progressive increase in watercourses competence (unit RM3). On the contrary, the second drainage deactivation (occurred around Kyr BP) broke an hydrological trend pointing to a progressive increase in watercourses competence. This disjointed event is interpreted to have be disconnected with any climatic forcing and probably was induced by rapid cut off of the drainage acted by cave-wall collapses. This event allowed the longest phase of human setting within the cave. 48

50 THE BALZA SOLETTA SECTION (CORVILLO BASIN, CENTRAL SICILY): AN EXAMPLE OF SECOND CYCLE MESSINIAN GYPSARENITES AND LAGO MARE DEPOSITS M. GRASSO 1, R. MANISCALCO 1, A. DI STEFANO 1, R. GENNARI 3, F. GROSSI 2, V. MANZI 3, M. ROVERI 3 and G. STURIALE 1 1 Dipartimento di Scienze Geologiche, Università di Catania, Corso Italia Catania, Italy 2 Dipartimento di Scienze Geologiche, Università di Roma 3, Largo S. Leonardo Murialdo, Roma - Italy 3 Dipartimento di Scienze della Terra, Università di Parma, Parco Area delle Scienze 157A Parma, Italy The Balza Soletta section is located along the Salso River, just north of the Alimena village. The section is a spectacular example of onlap of Second Cycle gypse-arenites onto the Calcare di Base. The older rocks are dipping nearly vertically, younging southwards into the Corvillo Basin. In the valley floor these carbonates are incised and the valley is filled with two large-scale composite sequences (each one about 500 m thick) with an overall fining and deepening-upward trend. The two sequences show an upward change of deltaic systems from fan deltas to river deltas, to delta-front lobes and by-pass deposits. The thickness of the upper sequence is probably overestimated due to backthrusts. The upper sequence is also characterised by the presence of ipohaline mollusc assemblages. The calcareous plankton association consists mainly of reworked specimens; the youngest age is assigned by the presence of the Messinian marker foraminifer Turborotalita multiloba. The lower sequence contains few horizons with rare ostracods (Cyprideis agrigentina, Loxoconcha mülleri and rare Candoninae indet. fragments). On the contrary the upper sequence shows several ostracod rich levels especially in the uppermost part where the association is exclusively composed by Cyprideis agrigentina and the foraminifer Ammonia. The SEM analyses on the sieve-pore shapes of C. agrigentina, performed on the uppermost samples, point to a hyperhaline environment (salinity estimated around 70 ). 49

51 PALEOCLIMATIC AND PALEOCEANOGRAPHIC VARIATIONS FROM THE LANGHIAN UP TO THE MESSINIAN IN THE MEDITERRANEAN AND COMPARISON WITH LOW-LATITUDE ATLANTIC OCEAN S. IACCARINO and E. TURCO Dipartimento di Scienze della Terra, Viale G.P. Usberti 157/A, Parma The Middle and Late Miocene is characterized by significant paleoclimatic and paleoceanographic changes, testified by geochemical and paleontological proxies and calibrated through high resolution stratigraphy. Following the Miocene Climatic Optimum occurred from the latest Burdigalian through the Langhian (17-15 Ma), the global climate changed to a colder mode, the ocean-climate system progressed to modern conditions marked by strong meridional and vertical thermal gradients, increased zonality and dominance of high-latitude deep water sources, and the continental areas reached a configuration similar to the modern one. The Middle Miocene global cooling is particularly evident from open ocean benthic oxygen isotope record (e.g. Zachos, 2001) which is punctuated by short-term episodes of δ 18 O increases reflecting ice growth phases and bottom water cooling (Mi events of Miller et al., 1991; 1996). Significant enrichment events occurred close to the Langhian/Serravallian boundary (Mi3b event) and the Serravallian/Tortonian boundary (Mi5 event) and during the Tortonian (Mi6 event) which have also been recorded from the Mediterranean (Turco et al., 2001; Abels et al., 2005). Finally, another significant paleoceanographic event which affected the Mediterranean area is the Messinian Salinity Crisis. These paleoclimatic and paleoceanographic variations are accompanied by significant changes within calcareous plankton assemblages both in Mediterranean and Atlantic Ocean. During the Miocene Climatic Optimum, the tropical and warm subtropical biotic provinces were widely distributed and the Mediterranean calcareous plankton assemblages show a great similarity with those from open ocean regions. The main features are, among others, the great abundance of Sphenolithus and the first step of Globorotalia fohsi lineage (i.e. G. peripheroronda) and the development of Praeorbulina/Orbulina lineage. The subsequent Middle Miocene global cooling favoured the contraction of tropical and subtropical bioprovinces to lower latitudes and calcareous plankton started to evolve differently between low-latitude and mid-latitude regions. The combined effects of global cooling and geodynamic evolution of the Mediterranean area (i.e. final closure of the connections between Tethys and Indian Ocean) led to the provincialization of the Mediterranean. Close to a major phase of Antarctic Ice Sheet growth (Mi 3b event), dated at Ma (Abels et al., 2005; Holbourn et al., 2005), calcareous plankton assemblages are characterized by the disappearance of Sphenolithus heteromorphus and Globorotalia fohsi peripheroronda in the Mediterranean. During the Serravallian the Globorotalia fohsi lineage completely developed in the Atlantic Ocean, whereas Paragloborotalia partimlabiata and Paragloborotalia mayeri are typical of the Mediterranean area. The late Serravallian to early Tortonian interval, characterized by relatively stable climatic conditions, is marked by Mi5 and Mi6 events which are respectively accompanied by the arrival of neogloboquadrinds in the Mediterranean from North 50

52 S. IACCARINO and E. TURCO Atlantic high latitudes (11.78 Ma) and the areal differentiation of Neogloboquadrina atlantica and N. acostaensis between high and mid latitudes (10.47 Ma). The vanishing of N. atlantica plexus from the Mediterranean and the mid-latitude North Atlantic coincides with the disappearance of Paragloborotalia siakensis in the equatorial Atlantic at Ma. The migration of N. acostaensis to low latitudes is delayed with respect to the Mediterranean, occurring only at 9.89 Ma. During the Messinian the Mediterranean experienced very restricted connections with the Atlantic Ocean which led to the onset of the Messinian Salinity Crisis at 5.96 Ma and had important effects on the planktonic and benthic organism distribution. From 7.24 Ma to 5.96 Ma the environmental conditions changed progressively from open to restricted marine waters. The carbon isotope pattern between 7.2 Ma and 6.8 Ma is explained as the result of progressive isolation of the Mediterranean and decreasing of bottom water ventilation. The positive values of oxygen isotope record are explained in terms of cooling and salinity increase approaching the deposition of the evaporites (e.g. Kouwenhoven et al., 2003). During the lastest Messinian (from 5.60 Ma to 5.33 Ma) more humid climatic conditions were responsible of increased continental run off and dilution of marine waters. In the lowest post-evaporitic deposits (P-ev 1 of Roveri et al., 2001, 2004, 2005) of the Apennine foredeep the absence of autoctonous marine microrganisms and ostracods is probably due to the dilution by continental run off and great depth, respectively. The deposits of the uppermost part of P-ev 1 and overlying post evaporitic unit (P-ev 2 of Roveri et al., 2001, 2004, 2005) are characterized by the presence of ostracods and infralitoral benthic foraminifera testifying a strong depth decrease. These sediments reflect an alternation of fresh water and infralitoral environments (Gennari et al. submitted) preceding the definitive re-establishment of open marine conditions in the Mediterranean at 5.33 Ma. REFERENCES ABELS H.A., HILGEN F.J., KRIJGSMAN W., KRUK R.W., RAFFI I., TURCO E., ZACHARIASSE W.J Long-period orbital control on middle Miocene global cooling: integrated stratigraphy and astronomical tuning of the Blue Clay Formation on Malta. Paleoceanography, 20. GENNARI R., IACCARINO S. MANZI V, AND ROVERI M. (submitted). The Messinian Zanclean boundary in the Northern Apennine, Stratigraphy HOLBOURN A., KUHNT W., SCHULZ M., ERLENKEUSER H Impacts of orbital forcing and atmospheric carbon dioxide on Miocene ice-sheet expansion. Nature, 438, KOUWENHOVEN T.J., HILGEN F.J., VAN DER ZWAAN G.J Late Tortonian-early Messinian stepwise disruption of the Mediterranean-Atlantic connections: constraints from benthic foraminiferal and geochemical data. Palaeogeog., Palaeoclim. Palaeoecol., 198, MILLER K.G., WRIGHT J.D., AND G.G. FAIRBANKS Unlocking the ice house: OligoceneMioceneoxygenisotopes, eustasy, andmarginal erosion, J. Geophys. Res., 96, MILLER K.G., et al., Drilling and dating New Jersey Oligocene-Miocene sequences: Ice volume, global sea level, and Exxon records, Science, 271, ROVERI M., BASSETTI M. AND RICCI LUCCHI F The Mediterranean Messinian Salinity Crisis: an Apennine foredeep perspective. Sedim. Geology, 140, ROVERI M., LANDUZZI A., BASSETTI M.A., LUGLI S., MANZI V., RICCI LUCCHI F. AND VAI G.B The record of Messinian events in the Northern Apennines foredeep basins, 32nd Intern. Geolog. Congress, Florence 2004, Field Trip Guide Book B-19 (2004) 44 pp. 51

53 S. IACCARINO and E. TURCO ROVERI M., BOSCOLO GALLO A., ROSSI M., GENNARI R., IACCARINO S.M., LUGLI S., MANZI V, NEGRI A., RIZZINI F. AND TAVIANI M The Adriatic foreland record of Messinian events (central Adriatic sea, Italy). GeoActa, 4, TURCO E., HILGEN F.J., LOURENS L.J., SHACKLETON N.J. AND ZACHARIASSE W.J Punctuated evolution of global climate cooling during the late Middle to early Late Miocene: High-resolution planktonic foraminiferal and oxygen isotope records from the Mediterranean. Paleocenography, 16, ZACHOS J., PAGANI M., SLOAN L., THOMAS E., BILLUPS K Trends, Rhythms, and Aberrations in Global Climate 65 Ma to Present. Science, 292,

54 MIDDLE-LATE MIOCENE RECORD FROM MEDITERRANEAN AND THE PARATETHYS AREA: TWO EXAMPLES FOR LONG-PERIOD VARIATIONS IN THE EARTH S OBLIQUITY AND THEIR RELATION TO THIRD-ORDER EUSTATIC CYCLES F. LIRER 1, M. HARZHAUSER 2, N. PELOSI 1 and W.E. PILLER 3 1 Istituto per l Ambiente Marino Costiero (IAMC)-CNR Napoli, Italy, 2 Museum of Natural History Vienna, Geological-Paleontological Department, Vienna, Austria, 3 Institute of Earth Sciences - Geology and Paleontology, Graz University, Austria Several authors suggested a relationship between glacio-eustatic sea-level oscillations and the 1.2 Myr long-periodic variations in obliquity. In this particular orbital configuration prominent oxygen isotope excursions to heavier values have been found (Lourens and Hilgen 1997; Turco et al. 2001; Zachos et al. 2001; Wade and Palike 2004; Abels et al. 2005). The Paratethys and the Mediterranean represent two key areas to test this scenario. The Middle Miocene Serravallian Stage (Mediterranean area) and Sarmatian regional stage (Paratethys area) and the Upper Miocene Tortonian Stage (Mediterranean area) and Pannonian regional stage (Paratethys area) represent crucial time interval for the Mediterranean-Paratethys system. The timing of the transition from the shallow-marine Sarmatian deposits up to the Pannonian continental strata of the central Paratethys represents a debate open problem as well as the transition between relatively deep-marine Badenian up to shallow-marine Sarmatian ones. Hydrocarbon drilling exploration in the Middle and Upper Miocene sediments of the Vienna Basin recorded a complete succession of marls and sands used as a marker-system for the regional the correlation of wells (Harzhauser and Piller 2004), where the thirdorder eustatic cycles in the Haq et al. (1987) curve are clearly marked by drastic change in depositional system. The astronomical tuning of high-resolution geophysical raw-data of the 2200 m long sedimentary interval of the OMV-well Eichhhron1 show the existence of low-frequency cycles linked to Milankovitch oscillations. In particular, power spectral analysis revealed the occurrence of significant frequency corresponding to periods of 1.2 My, 407kyr, 100kyr and 43kyr. Significant coherence at frequency corresponding to a period of 394ky confirms our tuning over the 400kyr eccentricity cycles. This astronomical tuning suggest that the Sarmatian/Pannonian and Badenian/Sarmatian boundaries have an age of and My respectively. The tuning of the Sarmatian/Pannonian records confirms that the beginning of the Lake Pannon is very close to the Miller event Mi5 and coincides with a period of minimum amplitudes in obliquity related to the 1.2-Myr cycle and coincides with the abrupt sea level drop TB 3.1. Moreover, the orbital configuration during the warmer period in between Mi5 and Mi6 corresponding with a maximum in the long-term 2.3 My eccentricity cycles, is confirms by the occurrence of lignites in the Paratethys record. The lignites facies which reflect the strong influence of 100 kyr eccentricity cycles correspond in the Mediterranean to small-scale and large-scale sapropel-clusters to 100 and 400 kyr eccentricity maxima. 53

55 F. LIRER, M. HARZHAUSER, N. PELOSI and W.E. PILLER In addition, the Badenian/Sarmatian boundary which falls close to the Miller event Mi4, which corresponds with a period of minimum amplitudes in obliquity related to the 1.2-Myr cycle, coincides with the sea level drop TB 2.6. Our results prove that Paratehtys sea-level drop which mark the Sarmatian/Pannonian transition and the Badenian/Sarmatian were dominantly obliquity controlled with additional influence of the100 and 400 kyr eccentricity cycles. REFERENCES ABELS H. A., HILGEN F. J., KRIJGSMAN W., KRUK R. W., RAFFI I., TURCO E., AND ZACHARIASSE W. J Long-period orbital control on middle Miocene global cooling: Integrated stratigraphy and astronomical tuning of the Blue Clay Formation on Malta. Paleoceanography, 20, HARZHAUSER M. AND PILLER W. E Integrated stratigraphy of the Sarmatian (UpperMiddle Miocene) in the western Central Paratethys. Stratigraphy, vol. 1, no. 1, HAQ B.U., HARDENBOL J. AND VAIL P.R Chronology of fluctuating sea levels since the Triassic. Science, 235, LOURENS L.J. AND HILGEN F.J Longperiodic variations in the Earth s obliquity and their relation to third-order eustatic cycles and late Neogene glaciations, Quat. Int., 40, TURCO E., HILGEN F.J., LOURENS L.J., SHACKLETON N.J., AND ZACHARIASSE W.J Punctuated evolution of global climate cooling during the late middle to early late Miocene: High-resolution planktonic foraminiferal and oxygen isotope records from the Mediterranean, Paleoceanography, 16, ZACHOS J., SHACKLETON N.J., REVENAUGH J.S., PALIKE H. AND FLOWER B. P. 2001, Climate response to orbital forcing across the Oligocene- Miocene boundary, Science, 292, WADE B.S., AND PALIKE H Ocean climate dynamics, Paleoceanography, 19, PA4019, doi: /2004pa

56 CROSS-STRATIFIED HYBRID ARENITES FROM THE PLIOCENE TRICARICO SUCCESSION (SOUTHERN APENNINES): INFLUENCE OF TIDAL CURRENTS AND HIGH-FREQUENCY RELATIVE SEA-LEVEL CHANGES ONTO LARGE-SCALE SUBAQUEOUS DUNES S. LONGHITANO 1, L. SABATO 2 and M. TROPEANO 2 1 Dip. di Scienze Geologiche, Università della Basilicata. Campus di Macchia Romana, Potenza. 2 Dipartimento di Geologia e Geofisica, Università di Bari. via Orabona 4, Bari. Cross-bedded, mixed bioclastic and siliciclastic sandstones of the Pliocene Tricarico succession of southern Apennines of Italy are organized into prominent, large-scale, unidirectional cross-stratification. The deposition is interpreted as produced by migrating subaqueous dunes on the floor of a 3-5 km wide, NE-trending seaway in water depths of m. These dunes are thought to have developed in response to strong, seawayparallel, tidal currents interlinking two adjacent parts within the same wedge-top basin. Based on increasing degrees of internal complexity, cross-stratification is organized into four hierarchical levels: (c1) cross-stratification or 1 st -order set; (c2) crossstratification or 2 nd -order set; (c3) cross-lamination or 3 rd -order set; and (c4) foresetlamination or 4 th -order set. Distinct attributes such as internal organization, cross-set thickness, foreset shape, and lower bounding-surface shape are used to describe and interpret the crossstratification. Bed thickness attributes of the cross-stratified strata show cyclical variation of alternating thicker and thinner beds, separated by lag of concentrated shell remains that repeats at regular stratigraphic heights. The Tricarico succession is interpreted to be the product of the sedimentation of a flood-tidal deltas developed in a shallow-water seaway. Individual cross-stratified successions are interpreted to have formed by dunes with varying sinuosity, superposition, and flow history, under conditions of different current strength but constant sediment production. Horizontally bedded successions are the result of robust, active dune fields that grew during times of vigorous sediment transport under the influence of highfrequency relative sea-level oscillations occurred during a dramatic subsidence of this part of the basin. Each single cross-stratified package of strata may represent parasequence set of clinoforms that develop during precise conditions of lowstand, rising, highstand and successive falling of the relative sea level. These induced changes in the basin depth, modifying the hydraulic section throughout reverse, tidal flows occurred. This condition alternatively increased and decreased flow velocity, producing erosion of different amplitude onto the surfaces of the migrating dunes. This process is the base of the model that we propose to interpret large-scale dunes developing under the influence of tidal flows and high-frequency relative sea-level changes. 55

57 THE ORIGIN OF THE MESSINIAN CALCARE DI BASE (SICILY, ITALY): EVAPORATIVE BUT CLASTIC V. MANZI 1, S. LUGLI 2, M. ROVERI 1 and B.C. SCHREIBER 3 1 Dipartimento di Scienze della Terra, Università di Parma, Via G.P. Usberti, 157/a, Parma, Italy 2 Dipartimento di Scienze della Terra, Universitá degli Studi di Modena e Reggio Emilia, Piazza S. Eufemia 19, Modena, Italy. 3 Department of Earth and Space Sciences, University of Washington, P.O. Box , Seattle WA 98195, USA According to the classical geological models for the Messinian salinity crisis (MSC), the Calcare di Base (CdB; Ogniben, 1957) of the Caltanissetta basin is considered a calcareous evaporitic and microbialitic deposit belonging to the Lower Evaporites (LE; Decima and Wezel, 1971; Decima et al., 1988) laterally equivalent of the primary selenite (Gessi di Cattolica; Selli, 1960). More recently (Garcia-Veigas et al., 1995; Rouchy and Caruso, 2006) CdB has been considered also a lateral equivalent of halite and, due to the local presence of halite and gypsum moulds, it was interpreted as a in situ collapse breccia produced by halite dissolution (autobreccia; Pedley and Grasso, 1993). The Calcare di Base is a composite unit of carbonate (variously calcite or aragonite; Decima et al., 1998), marls and locally gypsum. The most common facies is represented by a breccia made of carbonate mudstone forming m-thick beds. Its distribution is mainly limited to the Caltanissetta basin; the wedge-top and the foreland ramp basins are devoid of these carbonates (Roveri et al., 2006). Our studies revealed that, beside brecciated deposits indicating in situ collapse and/or very limited transport, most of the carbonate beds show very widespread sedimentary features like bed gradation, erosional bases, load structures and clay chips, suggesting a clastic origin and moderate distance transport through high- to low-density gravity flows. Cdb is never associated with massive selenites but more often with clastic and laminated gypsum. The latter may occur as isolated beds, or more commonly, gypsum and carbonate may be present within the same graded bed in different positions (e.g. gypsarenite on top of carbonate breccia or massive limestone topping gypsrudite beds); in the latter case a clastic origin seems reasonable and deposition from mixed gravity flows can be envisaged. Individual carbonate beds commonly show low lateral persistency and are commonly characterised by pinch-out terminations. Coarsening and thickening upward trends are also common features of the CdB unit. The Calcare di Base most commonly overlies Tripoli or, locally, gypsarenites or laminar gypsum, thus implying that its deposition, at least in some areas, postdates the clastic evaporites. CdB is capped by the Upper Evaporites (UE; Gessi di Pasquasia; Selli, 1960) locally showing clear onlap relations against it. The selenite beds of the UE are often wrongly regarded to as the Lower Evaporites (Gessi di Cattolica; Selli, 1960); actually, the latter are never observed in association with the CdB. The Calcare di Base is commonly present above structural culminations (intrabasinal topographic highs) and passes downslope to laminar gypsum deposits; it is here considered a syntectonic deposit formed above growing structural highs, which were progressively dismantled due to the ongoing uplift. In the inner Caltanissetta basin the CdB shows a clearly clastic character and reaches its maximum thickness, thus indicating 56

58 V. MANZI, S. LUGLI, M. ROVERI and B.C. SCHREIBER the main source areas. Coarsening upward sequences, widespread in the CdB, could witness the progressive uplift and rapid erosion of shallow-water carbonate factories. The Calcare di Base has been included in detailed cyclostratigraphic studies (Hilgen and Krijgsman, 1999; Bellanca et al., 2001; Rouchy and Caruso, 2006) to obtain an accurate datation of the onset of the Messinian salinity crisis, because the beginning of the evaporite phase is usually correlated to its base; moreover, the claimed cyclicity of this unit has been interpreted as precession-related. As previously suggested by Butler et al. (1995) most of these studies point to a diachronous onset of the MSC. We suggest that due to the mainly clastic origin of these deposits, the calibration of the CdB cyclical lithology with the astronomical parameters could be not correct; moreover, the CdB base is often unconformable and its deposition postdates the Lower Evaporites (Manzi et al., 2007). As a consequence, the diachronous nature of the base of the CdB could be more simply related to the intrinsically erosional character of this surface. Fig. 1 - Panoramic view of the Monte Gibliscemi section. As commonly observed in the Caltanissetta basin, when associated to primary gypsum deposits, the Calcare di base lies at the base of the Upper Evaporites (Gessi di Pasquasia); to the lowermost 4 cycles of Upper Evaporites are visible. A laminated clastic gypsum horizon is locally interposed between the two units. REFERENCES BELLANCA A., CARUSO A., FERRUZZA G., NERI R., ROUCHY J.M., SPROVIERI M. and BLANC-VALLERON M.M Sedimentary record of the transition from marine to hypersaline conditions in the Messinian Tripoli Formation in the marginal areas of the Sicilian Basin. Sedimentary Geology 139, BUTLER R.W.H., LICKORISH W.H., GRASSO M., PEDLEY H.M. and RAMBERTI L Tectonics and sequence stratigraphy in Messinian basins, Sicily: Constraints on the initiation and termination of the Mediterranean salinity crisis. Geological Society of America Bulletin, 107, DECIMA A. and WEZEL F.C Osservazioni sulle evaporiti Messiniane della Sicilia centromeridionale. Rivista Mineraria Siciliana , DECIMA A., MCKENZIE J.A. and SCHREIBER B.C The origin of evaporative limestones: an example from the Messinian of Sicily (Italy). Journal of Sedimentary Petrology 58, GARCIA-VEIGAS J., ORTI F., ROSELL L., AYORA C., ROUCHY J.M. and LUGLI S The Messinian salt of the Mediterranean: geochemical study of the salt from the Central Sicily Basin and comparison with the Lorca Basin (Spain). Bull. Soc. Géol. France 166, HILGEN F.J. and KRIJGSMAN W Cyclostratigraphy and astrochronology of the Tripoli diatomite Formation (pre-evaporite Messinian, Sicily, Italy). Terra Nova, 11, MANZI V., ROVERI M., GENNARI R., BERTINI A., BIFFI U., GIUNTA S., IACCARINO S.M., LANCI L., LUGLI S., NEGRI A., RIVA A., ROSSI M.E. and TAVIANI M The deep-water counterpart of the Messinian Lower Evaporites in the Apennine foredeep: The Fanantello section (Northern Apennines, Italy). Palaeogeography, Palaeoclimatology, Palaeoecology, doi: /j.palaeo OGNIBEN L Petrografia della serie solfifera-siciliana e considerzioni geotecniche relative. Mem. Desc. Carta. Geol. Ital. 33,

59 V. MANZI, S. LUGLI, M. ROVERI and B.C. SCHREIBER PEDLEY H.M. and GRASSO M Controls on faunal and sediment ciclicity within the Tripoli and Calcare di Base basins (Late Miocene) of central Sicily. Paleo3 105, ROUCHY J.M. and CARUSO A The Messinian salinity crisis in the Mediterranean basin: A reassessment of the data and an integrated scenario. Sed. Geol , ROVERI M., MANZI V., LUGLI S., SCHREIBER B.C., CARUSO A., ROUCHY J.-M., IACCARINO S.M., GENNARI R. and VITALE F.P Clastic vs. primary precipitated evaporites in the Messinian Sicilian basins. RCMNS IC PARMA 2006 The Messinian salinity crisis revisited II Post-Congress Field-Trip. Acta Naturalia De L Ateneo Parmense 42-1, SELLI R Il Messiniano Mayer-Eymar Proposta di un neostratotipo. Giornale di Geologia 28,

60 THE USE OF FORAMINIFERAL TESTS AS BIO-DRIFTERS: A NEW TOOL TO DEFINE LONGSHORE SEDIMENT FLOWS. AN EXAMPLE FROM PISA COAST (TUSCANY, ITALY) D. MEROLA and G. SARTI Dipartimento di Scienze della Terra, Via S. Maria 53, Pisa The planning of every defense project in a sandy coast demands to know how dynamic processes affecting the coast act and, particularly, how the sedimentary supply, coming from fluvial input, is distributed along the coast by littoral drifts. Beside welltested methodologies turned to the definition of the longshore sediment-flow (e.g. petrographic and textural analysis of the sands or artificial drifter-launch) less traditional methods, like geochemical analysis of the sediment and the study of bio-drifters can be used. This paper presents the preliminary results of a research carried out on the coast of Pisa and supported by Provincia of Pisa. Fossil foraminifers, picked from sandy samples, were used as natural drifters in order to define longshore sediment flows. Samples were collected at several depths along transects normal to the shore, from the foreshore zone to the shoreface zone up to the isobate of -10 meters. The costal area between Arno and Calambrone Rivers was sampled. Two main groups of foraminfera were distinguished: i) well preserved pliocenic foraminifers without any evidence of recrystalization and ii) bad preserved and recrystallized pre-pliocenic foramiferers. The first assemblage is characterized by the presence of Globorotalia puncticulata and Globigerinoides ruber-elongatus gr. while Paleocene-Eocene (eg. Morozovella and Acarinina) and Miocene (eg. Globigerinoides spp., Dentoglobigerina altispira gr) taxa prevail within the second assemblage. The preliminary results indicate that the first group exclusively characterizes the seaarea between Scolamatore River and Calambrone village while the second one develops along the coastal zone between Arno River and Tirrenia village. In order to know the feed area of these two foraminiferal assemblages additional samples were collected in Arno and Calambrone rivers. The acquired data indicate that the Pliocenic foramifers are carried by Calambrone River while pre-pliocenic associations are typical of the sands transported by Arno River. Therefore, the presence of a northward drift (from Calambrone River to Calmbrone village) and of a southward drift (from Arno River to Tirrenia village) can be inferred and reveals a drift-convergence zone, in agreement with the results of previous works based on different methodologies. In conclusion, the use of foramiferal assemblages to define longshore sediment-flows seems to be a very promising tool, particularly in coastal zones fed by fluvial systems that drain different alimentation areas. 59

61 PARATETHYAN FAUNAS IN THE TORTONIAN SUCCESSION OF THE CARG-FVG S6 COL VERGNAL DRILLING (FRIULI, NE ITALY) G. MONEGATO 1, C. FARANDA 2, R. GATTO 3 and S. LIGIOS 2 1 Dip. Georisorse e Territorio, Università di Udine, Via Cotonificio 114, Udine. 2 Dipartimento di Scienze Geologiche, Università degli Studi di Roma Tre, L.go Murialdo, Roma. 3 Dip. Geoscienze, Università degli Studi di Padova, Via Giotto 1, Padova. The 105,7 m deep drilling made by CARG-FVG Project at the end of the Tagliamento valley, near the Vergnal hill of Osoppo, shows the stratigraphy of the Quaternary deposits of the Osoppo field. Their substratum, cored at the basal 16 m of the drilling, is made by silty-sand laminated beds with minor sandstone layers; locally organic debris and mollusc shell clusters occur. The substratum has been investigated with a dense sampling and analyses of the recovered fauna, consisting of ostracods, gastropods and ophiuroids, yielded some unexpected data. The ostracods are well-preserved and characterised by medium-high frequency, especially around m and m. The autochthonous species represent a monotonous and oligotypic association dominated by Hemicyprideis dacica, with Hemicytheria peijnovicensis and Loxoconcha josephi. The first two species are characteristic of shallow brackish-water environments related to the Paratethyan palaeogeographic domain during the Pannonian. These species have been recovered in the Italian successions for the first time. The gastropods are represented by minute and compactionally distorted specimens of Planorbidae and Stenothyroides sp. Planorbids are frequent especially between and m, whereas Stenothyroides specimens occur between and m. This is the first record of Stenothyroides in the Italian Neogene and possibly the most recent record of the genus for the Mediterranean region. The ophiuroids occur between m as isolated ossicles, mainly vertebrae, and arm fragments. They never co-occur with gastropods. At the local scale, the result of these analyses changes the interpretation of the substratum of the Osoppo field, always considered made by Eocene flysch (Giorgetti and Stefanini, 1989), with important implication on the tectonic setting of the area. At a regional scale these faunas prompt to make intriguing hypotheses about the late Miocene setting of the Veneto-Friuli Basin (Massari et alii, 1986), suggesting new palaeogeographic arrangements for this area. Alternatively: - the Veneto-Friulian Basin was separated from the Mediterranean and connected by a sea-way with the western part of the Paratethys, currently assumed closed during the Serravallian (Jolivet et alii, 2006); - the Veneto-Friulian Basin was isolated both from the Mediterranean and from the Parathetys. The Paratethyan ostracods spread westwards passively by aquatic birds. REFERENCES GIORGETTI F. and STEFANINI S., Vulnerabilità degli acquiferi del Campo di Osoppo-Gemona all inquinamento (Provincia di Udine). C.N.R. GNCI Regione Autonoma Friuli V.G., Trieste. 60

62 G. MONEGATO, C. FARANDA, R. GATTO and S. LIGIOS JOLIVET L., AUGIER R., ROBIN C., SUC J.-P. and ROUCHY J.-M., The internal geodynamic context of the Messinian Salinity Crisis. In: Rouchy J.-M., Suc J.-P., Ferrandini J., Ferrandini M. (Eds.), The Messinian Salinity Crisis Revisited, Sediment. Geol , MASSARI F., GRANDESSO P., STEFANI C. and ZANFERRARI A., The Oligo-Miocene Molasse of the Veneto- Friuli region, Southern Alps. Giorn. Geol. 48,

63 SOFT-SEDIMENT DEFORMATION INDUCED BY SINKHOLE ACTIVITY IN SHALLOW MARINE ENVIRONMENTS: A FOSSIL EXAMPLE FROM THE CALCARENITE DI GRAVINA FORMATION IN THE MONOPOLI AREA (LATE PLIOCENE-EARLY PLEISTOCENE, APULIAN FORELAND, SOUTHERN ITALY) M. MORETTI 1, G. OWEN 2 and M. TROPEANO 1 1 Dipartimento di Geologia e Geofisica e Centro Interdipartimentale di Ricerca per la Valutazione e Mitigazione del Rischio Sismico e Vulcanico, Università di Bari, Via Orabona 4, Bari, Italy 2 Department of Geography, University of Wales Swansea, Singleton Park, Swansea SA2 8PP, UK Large scale soft-sediment deformation exposed in sea cliffs in the Cala Corvino area, close to the town of Monopoli (Adriatic coast, southern Italy), involves the base of the Calcarenite di Gravina Formation (late Pliocene-early Pleistocene), a shallow marine carbonate unit transgressively overlying Cretaceous limestones. Locally the formation is about 15 m thick and the base crops out at sea level. Previous work described the main sedimentological features of the Plio-Pleistocene succession, which records a deepening upward trend punctuated by minor regressive episodes (D'Alessandro and Iannone, 1982; 1983). The lower part of the succession (up to 3 m thick) is characterized by calcareous sands and gravels with terrigenous rounded fragments coming from the Cretaceous limestones, and was interpreted as a forcedregressive coastal body by Tropeano (1993) and Tropeano and Sabato (2000). The middle and upper part of the succession is characterized by grainstones and packstones whose palaeoecological features were interpreted as representing littoral or sublittoral environments (D'Alessandro and Iannone, 1982; 1983). Soft-sediment deformation structures (load casts) in the lower part of the succession (D'Alessandro and Iannone, 1982; 1983) were attributed to liquefaction of sands and sinking of the underlying gravels (Tropeano, 1993). New field data indicate that soft-sediment deformation involved not only the "terrigenous" part of the Plio-Pleistocene succession but a basal zone approx. 6 m thick; deformation is totally absent in the overlying part of the same succession. Soft-sediment deformation structures are represented by large-scale collapse features whose general morphology may be linked to irregularly elongated conical zones of sinking. In vertical section, narrow drop zones occur in the sandy-gravelly facies and large gentle folds in the underlying grainstone-packstone beds. In plan view, sinking zones are elliptical; they are not randomly located but are aligned NW-SE. In one well exposed section, one of these sinking zones is directly linked to a sinkhole in the bedrock. Smaller scale softsediment deformation structures occur laterally adjacent to the main conical collapse structures, as described by Tropeano (1993). They are represented by narrow and vertically elongated load-structures (up to 2 m high and cm width); in some places, where bedrock crops out, they are closely related to fractures of the Cretaceous limestones. The highest bed involved in the deformation shows a lower surface with concave-up morphology (in the upper part of the large-scale collapse structures) and a flat upper boundary; the concave up surfaces are gentle folds (synclines) that record deformation during sedimentation of grainstone/packstone facies of this layer. The bulk of the data suggests that all the varieties of the soft-sediment deformation structures are genetically related and formed instantaneously during the sedimentation of 62

64 M. MORETTI, G. OWEN and M. TROPEANO the highest deformed layer. Deformation was probably triggered by the sudden opening of bedrock fractures, inducing both large collapses into sinkholes and, laterally, smaller sinking structures in the overlying, unconsolidated sediment. Soft sediment deformation occurred in a shallow marine setting and caused intense deformation of the sea floor. The trigger for such soft-sediment deformation induced by the opening of fractures in bedrock may be tentatively attributed to extensional phenomena induced by either tectonics (faulting and/or seismic shock) or karstic processes, or a combination such as the seismic activity in the presence of a karstic substrate. REFERENCES D'ALESSANDRO A. and IANNONE A Pleistocene carbonate deposits in the area of Monopoli (Bari Province): sedimentology and palaeoecology. Geologica Romana, 21, D'ALESSANDRO A. and IANNONE A Prime considerazioni sedimentologiche e paeoecologiche su alcune sezioni della Calcarenite di Gravina (Pleistocene) nei pressi di Monopoli. Università di Bari, Studi Geologicie Geofisici sulle regioni Pugliese e Lucana, XXVII, 16 pp. TROPEANO M., Strutture sedimentarie deformative in calcareniti di spiaggia plio-pleistoceniche (versante adriatico delle Murge). Giornale di Geologia, 55/1, TROPEANO M. and SABATO L Response of Plio-Pleistocene mixed bioclastic-lithoclastic temperate-water carbonate systems to forced regressions: the Calcarenite di Gravina Formation, Puglia, SE Italy. Geological Society Sp. Publ. 172,

65 TRIGGER MECHANISM RECOGNITION OF THE SOFT-SEDIMENT DEFORMATION IN THE UPPER MESSINIAN DEPOSITS OF THE GARGANO PROMONTORY (APULIA, SOUTHERN ITALY) M. MORSILLI 1 and M. MORETTI 2 1 Dipartimento di Scienze della Terra Università di Ferrara, via G. Saragat 1, Ferrara (Italy) 2 Dipartimento di Geologia e Geofisica - Centro Interdipartimentale di Ricerca per la Valutazione e Mitigazione del Rischio Sismico e Vulcanico Università degli Studi di Bari,via E. Orabona 4, Bari (Italy) Soft-sediment deformation structures have been found in some upper Messinian transitional deposits, probably equivalent to the widespread Lago-Mare event (Cita, 1978, Cipollari et al., 1999, Cosentino et al., 2005, Clauzon et al., 2005; Orszag-Sperber, 2006), named as calcari di Fiumicello in the new geological map (CARG Project, Morsilli et al., in press). This lithostratigraphic unit, about 30-40? meter thick, crops out in the northern part of the Gargano Promontory near Cagnano Varano. Four detailed stratigraphic sections have been measured and sampled along some rail cuts. The succession consists of an alternation of well bedded limestone, marly limestone, marls and lime mud, with few conglomerate layers. Limestone texture is made by superficial ooids (mainly dissolved and sometimes recrystallized) or intraclastic grainstone to packstone, arranged in 10 to 120 cm thick beds frequently cross laminated and cross stratified (current and wave ripple, bidirectional and sigmoidal lamination at dune scale, low angle planar laminations). Grain size range from fine to very coarse sand. Marly limestone and marls, white to light brown in colour, shows a variable bed thickness from 2 to 50 cm with very thin, mm-scale, even laminations. Conglomerate layers, mainly 5 to 15 cm in thickness, are visible in various intervals of the stratigraphic sections. They consist mainly of orthoconglomerate with clasts up to 2-6 cm in diameter, derived from the Serravallian- Tortonian interval of the Pietra Leccese formation. Paraconglomerates with a sandy matrix are visible only at the top of the section 1 where the bed thickness increase up to 30 cm. Elongated clasts reaches the maximum size of about 10 cm. Exposure surfaces are testified by thick root traces visible in the marly intervals and also in some conglomerate bed of the Section 3. Macrofossils are not visible in the measured sections and microfossils in thin sections are mainly reworked and consists of fragments of benthic and planktonic foraminifera. There are also some fossils not reworked as miliolids and ostracods. The calcari di Fiumicello paraconformably overlay a thick red-matrix conglomeratic unit interpreted as alluvial fan to fan delta deposits. The upper limit is not known. Tectonic deformation is very gentle with a general tilting toward NE and some broad folds with NNW-SSE axis occur. Only in the section 1 there are present some small normal faults with few decimetre downthrow. Some features like beds thickness changes, small dykes and onlap in a small graben like structure seem to suggest the presence of synsedimentary deformation at least in this part of the succession. On the base of the lithologies, texture and sedimentary structures, five main lithofacies has been recognized and interpreted as indicative of a barrier island-lagoon system like the modern Lake of Varano. The various sub-environments are: 1) very low energy lacustrine? with stressed salinity condition or Eh=0 at the water-sediment interface 64

66 M. MORSILLI and M. MORETTI testified by the absence of epifauna and infauna (mm thick laminations); 2) shallow protected lagoon sometimes with terrestrial? plants (root traces); 3) small internal beaches made of pebbles or sand size grains (foreshore low angle planar laminations); 4) small coarse grained deltas (paraconglomerate); 5) flood delta and/or small tidal bars (m-scale sigmoidal and bidirectional lamination). Soft-sediment deformation affects the entire late Messinian succession and occurs in different discrete intervals (15 deformed beds) separated by undeformed beds. The rail cuts allow us to follow the deformed beds along hundreds of meters and the direct observation of lateral variations in the style and degree of deformation. By a morphological point of view, they are represented mainly by load-structures with minor water-escape features while only one deformed bed contains distorted lamination and irregular folds. The detailed analysis of the deformation features allows us to affirm that deformation occurred during and after sedimentation and that mechanisms of deformation (sensu Owen, 1987) were different: some are clearly related with liquefaction and/or fluidization (viscous-fluid behaviour in load- and water-escape structures) while some show plastic and/or viscous behaviour (distorted lamination and irregular folds). Excluding the action of overloading processes and the action of storm-waves, the reliable trigger mechanisms for the observed deformed beds are seismic shocks. Nevertheless, the main interest of this work is related with the lateral variation in the style and degree of deformation in the single deformed beds. In fact, one of the most accepted criteria to recognize seismic-induced deformations (seismites, sensu Seilacher, 1969) is the large lateral extension of the deformed beds (see for example, Sims, 1973). In our example, locally, highly deformed beds pass laterally (without an appreciable preferred direction of variation) to totally undeformed beds or single deformed beds pass laterally to two thinner beds separated by an undeformed surface. Having excluded the presence of erosional surfaces, we think that lateral variations in bed attributes (texture, presence of matrix, porosity, water content, early-diagenetic features, etc.) could be able to control the lateral extension of the seismic shock effects on saturated soft-sediments. REFERENCES CIPOLLARI P., COSENTINO D., ESU D., GIROTTI O., GLIOZZI E. and PRATURLON A Thrust-top lacustrine-lagoonal basin development in accretionary wedges: late Messinian (Lago-Mare) episode in the central Apennines (Italy). Palaeogeogr. Palaeoclimatol. Palaeoecol. 151, CITA M.B., RYAN W.B.F. and KIDD R.B Sedimentation rates in Neogene deep sea sediments from the Mediterranean and geodynamic implications of their changes. In: Leg 42A (Ed. by K.J.Hsu and L.Montadert, et al.), Init. Rep. Deep Sea Drill. Proj. 42(1), COSENTINO D., CIPOLLARI P., LO MASTRO S. and GIAMPAOLO C High-frequency cyclicity in the latest Messinian Adriatic foreland basin: Insight into palaeoclimate and palaeoenvironments of the Mediterranean Lago-Mare episode. Sedimentary Geology 178, ORSZAG-SPERBER F Changing perspectives in the concept of Lago-Mare in Mediterranean Late Miocene evolution. Sedimentary Geology , OWEN G Deformation processes in unconsolidated sands. In: M. E. Jones and R. M. F. Preston: Deformation of Sediments and Sedimentary Rocks. Geological Society Spec. Publ. 29, SEILACHER A Fault-graded beds interpreted as seismites. Sedimentology 13, SIMS J.D Earthquake-induced structures in sediments of Van Norman Lake, San Fernando, California. Science 182,

67 GEOLOGICAL AND GEOTECHNICAL CHARACTERIZATION OF THE SUBSOIL OF ROMA (ITALY): SPATIAL MODELLING OF THE UPPER PLEISTOCENE-HOLOCENE ALLUVIAL DEPOSITS BY MEANS OF MULTIVARIATE GEOSTATISTICS M. MOSCATELLI 1, G. RASPA 2, F.P. STIGLIANO 1, R. VALLONE 1, A. PATERA 3, M. MANCINI 4, G.P. CAVINATO 1 and S. MILLI 5,1 1 CNR-IGAG, Istituto di Geologia Ambientale e Geoingegneria, Via Bolognola 7, Roma. 2 Dipartimento di Ingegneria Chimica, dei Materiali, delle Materie Prime e Metallurgia, Università di Roma La Sapienza, Via Eudossiana 18, Roma. 3 INGV, Istituto Nazionale di Geofisica e Vulcanologia, Via Donato Creti 12, Bologna. 4 INGV, Istituto Nazionale di Geofisica e Vulcanologia, Sezione di Sismologia e Tettonofisica, Via di Vigna Murata 165, Roma. 5 Dip. di Scienze della Terra, Università di Roma La Sapienza, Piazzale Aldo Moro 5, Roma. The Institute of Environmental Geology and Geoengineering (IGAG) of the National Research Council of Italy (CNR) during the last three years has coordinated a multidisciplinary research group to develop an integrated geological-geotechnical model of the subsoil of the city of Roma, Italy. The model of the subsoil of Roma that CNR- IGAG is developing consists of the integration and analysis of the main geological and geotechnical data: stratigraphy, lithology and texture, physical and mechanical properties, hydrogeology. This model, which is at present under construction, will be the core of a GIS oriented to define, prevent, and manage the geohazard of Roma. Information from more than 6000 wells including hydrogeologic and continuous coring boreholes, together with detailed geological maps, measured stratigraphic logs, and geotechnical in situ tests, were homogenized and archived in a personal geodatabase with the support of ArcGIS application by ESRI Inc. The research was mainly focussed on the upper Pleistocene-Holocene alluvial deposits, essentially related to the Tevere and Aniene rivers. Information of more than 2000 boreholes penetrating the alluvial deposits was encoded and elaborated using geostatistics. Alluvial sedimentary bodies are currently reconstructed by means of physical-stratigraphic and geostatistical methodologies. The relationships between physical and mechanical parameters of the samples are also investigated using multivariate geostatistics. Application of these methodologies demonstrates their validity for a preliminary stratigraphic-sedimentological and geotechnical characterization of alluvial deposits. Nevertheless, the future challenge of the research will be the proper integration of the geological and geotechnical information to finally accomplish a geotechnical model of the subsoil of Roma. Results of this work will be a useful tool for developing a tough procedure aimed at modelling the geological-geotechnical properties of subsoil. On this regard, CNR-IGAG is now focussing a relevant part of its activity on the UrbiSIT project, financed by the National Civil Protection Agency of Italy for the geohazard definition and prevention in large urban areas by means of GIS technologies. 66

68 SILICICLASTIC VS. CARBONATE SEDIMENTATION IN A LOW ENERGY EMBAYMENT: THE PLIOCENE VAL D ORCIA BASIN (TUSCANY, ITALY) R. NALIN 1 and M. GHINASSI 2 1 Geoscience Research Institute, Campus Street, Loma Linda, CA 92350, USA. 2 Dipartimento di Geoscienze, Università degli Studi di Padova, Via Giotto 1, Padova, Italy. Amongst the numerous ecological and physical factors controlling the onset of carbonate sedimentation, the composition of substrate and basin margin rocks plays an important role by influencing the degree of water turbidity and terrigenous influx. The relevance of this parameter was explored in the study of a mid-pliocene sequence within the sedimentary infill of the Val d Orcia Basin (Tuscany, Italy), where shallow water facies in the transgressive systems tract record coeval development of carbonatedominated deposits just a few kilometres apart from siliciclastic accumulations. The Val d Orcia Basin has an aerial extension of about 80 km 2, and its Neogene infill, m thick, consists of four unconformity-bounded units. The third unit, Pliocene in age, is partitioned in three higher frequency depositional sequences, whose uppermost is investigated in this study. The transgressive siliciclastic deposits of this sequence consist of about 10 m thick sands overlying a basal shell-rich gravelly lag. The sands show a definite fining upward trend, varying from coarse to very fine in size, and form tabular horizontal beds ranging from 3 to 15 cm in thickness. Physical structures are scarce and beds are deeply amalgamated because of intense bioturbation. Shells and plant debris are locally common. The coeval transgressive carbonate deposits developed in an area confined to the north-eastern sector of the basin, and show an overall tabular geometry with a thickness of up to 13 m. They consist of coralline algal rudstone and packstone, dominated by algal branches up to 2 cm long dispersed in a fine micritic matrix. Rhodoliths up to 8 cm in diameter locally occur as infill of small irregular scours up to 60 cm wide and 40 cm deep, or as decimetric mound-shaped accumulations showing traces of incipient binding in their upper portion. Bivalves, in places preserved as thin shellbeds, echinoids, bryozoans, benthic foraminifera, and barnacles are subordinate components of the association. Bioturbation is ubiquitous and only a faint bedding is distinguishable. Sedimentological characteristics of both siliciclastic and carbonate units suggest a low hydrodynamic energy depositional setting, probably related to the embayed morphology of the basin clearly indicated by palaeogeographic reconstructions. It is suggested that in such restricted environment, where alongshore sediment transport and wave reworking were probably scarce, the lithological composition of the basin margins played a key feature in controlling the instauration of carbonate factories. In the north-eastern sector of the basin, where carbonates are preserved, the bedrock consists of competent limestone which supplied a low amount of suspended load to the basin. On the other hand, siliciclastic sedimentation took place along the margins where bedrocks consist of more erodible Cretaceous siltstone and arenite. 67

69 NORTH SARDINIA SANDY SHORE HUMAN IMPACT AND PRESERVATION: THE CASE OF LA PELOSA BEACH V. PASCUCCI 1, A. CARTA 1, S. ANDREUCCI 1 and S. CAPPUCCI 2 1 Istituto di Scienze Geologico-Mineralogiche, Università di Sassari 2 ICRAM, Via Casalotti 300, Roma North Sardinia represents a key area to analyze combined effects of human impact and preservation of sandy shore. The La Pelosa is one of the most beautiful and famous sandy beach of Sardinia. It is located in the northwestern most part of the Asinara Gulf (Fig. 1). The Gulf, in this part is protected by the elongated Asinara Archipelago from the open Sardinia Sea to the west (Carmignani et al., 2001). The open sea is connected with the Gulf through a narrow and relatively shallow strait (Passaggio della Pelosa). The La Pelosa beach formed as an isolated cusp in a shadowed part of the strait where small islands (Piana Is., is the most important) protect the coast from the strong NW coming winds (Fig. 1). Here, the interaction between reduced energy waves coming from NW (Mistral dominated) and NE (Greco dominated) has allowed the deposition of fine sand, main sediment composing La Pelosa beach. From the past 30 years the beach has suffered several periods of erosion and growth mainly related to climatic changes (wind and waves regimes), and human impact, very high during summertime (Cappucci and Pascucci, 2004). Fig. 1 Satellite image of the studied area from Google Earth. SW= sand waves; dashed lines are the Multi Beam survey. We have monitored the evolution of the La Pelosa beach through the analysis of aerial photos and satellite images acquired during , Multibeam (MB) and Side 68

70 PASCUCCI V., CARTA A., ANDREUCCI S. and CAPPUCCI S. Scan Sonar (SSS) surveys, and direct diving in selected areas of the submerged part of the beach. La Pelosa beach is characterized by a relatively well developed beachface with up to 5m dunes in the backshore and a narrow shoreface. Both beachface and shoreface parts are mainly composed of fine bioclastic sand with a silicoclastic fraction never exceeding 10%. Ripples are NW-SE oriented. A relatively steep (20 ) scarp separates the shoreface from the offshore. The offshore part is composed of medium sand mainly bioclastic. Sand waves are the most recurring sedimentary structure. They are up to 50m long and 3-4m high, NE-SW oriented, and draped by asymmetrical ripples. Multibeam and Side Scan Sonar data indicate that Passaggio della Pelosa strait is interested by the presence of several meter scale sand waves migrating toward the SE. In particular MB has imaged that sand coming from the sand waves is flooding Posidonia meadow located south of the La Pelosa (Fig. 2). Fig. 2- Multi Beam image. SW= sand waves; P= Posidonia meadow. Main source of the bioclasts forming La Pelosa beach sand is the Posidonia meadow. Apparently no other sedimentary sources are feeding the beach. Results of this study indicate that the subaerial part of the La Pelosa beach reduced from the m 2 of the 1977 to the m 2 average of the Most of the eroded sand is carried offshore and transported toward SE into the Asinara Gulf. A relatively small amount of sand is, instead, transported northward and deposited on outcropping rocks. A change in wind regime has been documented in the last 30 years. The strong winds coming from NW are less frequents and winds coming from NE or E are instead common and occasionally very intense. This has generated a change in sediment transport. The weak equilibrium that has allowed the formation of the La Pelosa beach cusp is, therefore, broken. No sediment are coming from inland because of intense concretization of the coast. The only possible sediment source is the Posidonia meadow that, however is flooded by the sand coming from the eroded beach (Fig. 2). Only north of La Pelosa is recorded a gentle arrive of sediment. Therefore, a possible future scenario 69

71 PASCUCCI V., CARTA A., ANDREUCCI S. and CAPPUCCI S. could be the complete erosion of the La Pelosa beach and the formation of a new sandy beach to the north controlled by NE and E winds. REFERENCES CARMIGNANI L., OGGIANO G., BARCA S., CONTI P., SALVADORI I., ELTRUDIS A., FUNEDDA A. AND PASCI S Note illustrative della Carta Geologica della Sardegna a scala 1: Memorie descrittive Carta Geolologica Italiana, 60, 283 pp. CAPPUCCI S. AND PASCUCCI V Preliminary results of a multidisciplinary investigation on La Pelosa beach, Stintino, Northwest Sardinia, Italy. 23 rd IAS Meeting of Sedimentology, Coimbra (Portugal), September 2004, Abstracts book, p

72 ENVIRONMENTAL CONTROLS ON FRESHWATER CARBONATE (TUFA) DEPOSITION M. PEDLEY Department of Geography, University of Hull, Hull, HU6 7RX, U.K. Existing tufa depositional models are based on a continuum of bedform associations. Controls on their development include flow velocity, turbulence, calcium ion concentration and biofilm colonisation rate. Seasonal temperature and water supply controls lead to 'climatic' variations within the models. Water supply in each model can vary from single and multiple point sourced resurgences (e.g. perched springline and fluvial barrage tufas), to line sourced resurgences where the water supply generally enters via a breached aquifer exposed in the valley side and floor (e.g. paludal and lacustrine tufas). Low magnesian-calcite is deposited in the immediate vicinity of resurgences with calcium ion concentrations decreasing with distance from supply. Consequently, the topography within any model faithfully reflects Ca ion availability. We have found, from several years of routine monitoring of the Rivers Lathkill, Wye and Welton Beck (N. England), and Afon Pant-Gwyn (NE Wales) that significant macro-scale precipitation occurs where dissolved CaCO 3 concentration exceed 225 mg/l. However, in order to unravel precisely the processes controlling natural systems, we have developed a multiple mesocosm facility at Hull. Currently, we have 5 independent flume mesocosms from which we record Ca saturation, ph and temperature on a 24/7 basis. Periodically, the recycled water is also analysed for Al, Fe, K, Mg, Na, P, S, Si and Sr in order to monitor life support requirements. A calcium reactor is linked to Flume 5 and supplies and maintains Ca ions to desired concentrations. Initial experiments have focussed on biofilm processes. Their presence rapidly modifies the dissolved ion composition of the flowing flume water. In particular, experiments show preferential selection for Ba over Ca and Ca over Mg. By experimenting with biofilm colonised probes we can also demonstrate the role of the biofilm in the precipitation process. In fact, the biofilm creates a diffusion gradient between the flume water and chelated Ca ions within the EPS. Precipitation appears both within the EPS and at the base of the biofilm. This work provides the first process orientated evidence that biofilms significantly increase the rate of carbonate precipitation in freshwater environments. 71

73 GEOLOGICAL FEATURES OF THE OUTER BORDER OF SOUTHERN APENNINES, BETWEEN S. MAURO FORTE, OLIVETO LUCANO AND ACCETTURA (BASILICATA-SOUTHERN ITALY) M. PEPE Dipartimento di Geologia e Geofisica, Università degli Studi di Bari The studied area is located in the Basilicata region, between San Mauro Forte, Oliveto Lucano and Accettura vil lages, along the outer border of South-Apenninic thrust belt (Basilicata-Southern Italy). The geological framework of this area is characterized by a Neogene accretionary wedge, which consists of Cretaceous to Miocene pelagic and turbidite units, overlaid by Pliocene coastal to emipelagic wedge-top deposits. Detailed stratigraphic and structural observations and a geologic survey, carried out on scale of 1:10.000, demonstrate that locally the outcropping part of the accretionary wedge is composed of three main tectonic units bounded by two NNW-SSE thrust surfaces. In particular, the inner thrust surface has a flat geometry, whereas the outer one is characterized by a ramp geometry and can be related to the "Stigliano ramp" of Patacca and Scandone (2001). Each tectonic unit is made up of relatively continuous sedimentary successions, in which stratigraphic units are recognized. These latter, referred to wellknown formations, belong to different and diachronous sedimentary basins developed on the western margin of Adria Plate (Tyrrenian Basin; Lagonegro Basin; Numidian Basin; Irpinian Basin). In particular, the upper tectonic unit is composed, from bottom to top, of the Argille Variegate Formation (sensu Ogniben, 1969), upper Cretaceous to Eocene in age, which outcrops with a thickness of about 200 m, the Tufiti di Tusa and/or Arenarie di Corleto (sensu Ogniben, op. cit.), an Oligocene to lower Miocene unit, about 100 m thick, the Flysch di Gorgoglione (sensu Ogniben, op. cit.), of lower-middle Miocene age, about 500 m thick. The intermediate tectonic unit is represented by the Flysch Rosso (sensu Scandone, 1967), an Eocene-Oligocene unit, which outcrops with a thickness of about 150 m, the Numidian Flysch (sensu Ogniben, op. cit.), of Burdigalian age, about 700 m thick. Finally, the lower tectonic unit is made up of the Numidian Flysch, with a thickness of about 250 m, and the Serra Palazzo Formation (sensu Selli, 1962), upper Burdigalian to Serravallian in age, more than 300 m thick. Taking into consideration the sedimentary successions observed in each tectonic unit, together with their structural position, it is possible to refer the three tectonic units, from top to bottom, to Pietrapertosa, Vaglio di Basilicata and San Chirico tectonic units identified by Pieri et al. (2004) in Campomaggiore and Tricarico areas. Pliocene wedge-top deposits rest unconformably on the Numidian Flysch and on Serra Palazzo Formation belonging to San Chirico tectonic unit, although some strips of Pliocene deposits are also recognized on the Pietrapertosa tectonic unit. Pliocene wedgetop deposits are represented by three different sedimentary sequences, bounded by two angular unconformities. The first sequence, early Pliocene in age and about 150 m in thickness, is made up of massive fine-grained sands of distal delta front facies, evolving to clayey silts with interbedded sands, of prodelta environment. The second sequence, middle to late Pliocene in age and up to 120 m thick, consists of sands with interbedded conglomerates, of distal delta plain facies, passing to silty sands and calcarenites with progradational geometries, or to massive sands and tabular beds of conglomerates, of 72

74 M. PEPE delta front environment. The third sequence, late Pliocene in age and more than 100 m thick, is composed of hybrid arenites, of shoreface facies, evolving to shelf claystones. This study allowed to obtain a new geological picture of this margin of the Southern apennines, useful to reconstruct the last deformation phases that conditioned the stratigraphic and sedimentologic features of the Pliocene wedge-top basin deposits. 73

75 FORAMINIFERAL RECORD AND ASTRONOMICAL CYCLES: AN EXAMPLE FROM THE MESSINIAN PRE-EVAPORITIC GELLO COMPOSITE SECTION (TUSCANY, ITALY) F. RIFORGIATO 1, L.M. FORESI 1, M. ALDINUCCI 1, R. MAZZEI 1, F. DONIA 1, R. GENNARI 2, G. SALVATORINI 1 and F. SANDRELLI 1 1 Dipartimento di Scienze della Terra, Università di Siena, Via Laterina 8, Siena 2 Dipartimento di Sc. della Terra, Università di Parma, Parco Area delle Scienze 157A, Parma A high resolution bio-magneto and cyclostratigraphical study has been carried out for the first time on Messinian pre-evaporitic marine deposits (Gello Composite Section) from the Volterra Basin (Italy). The Gello Composite Section is about 60m thick and comprises two adjoining parts: the lower part (Section 1, about 50m thick) include dominantly massive grey marly clays and marls with intervening thinly-laminated marly clays (<2m) and a sandy gravel bed (max 30cm) in the lower and middle part of the section, respectively. The upper part (Section 2) consists of about 9m thick massive marly clays bearing in its middle part a 10cm thick layer made up of corals not in life position. It ends with a few meters of alabastrine gypsum, whose correlative gypsum exposed elsewhere in the basin consists of selenite and manifests the evaporitic phase of the Messinian Salinity Crisis. About 400 samples, with an average spacing of 15cm, have been cored and characterized in terms of micropaleontological, sedimentological, geochemical (calcimetric analysis) and geophysical (magnetic susceptibility and paleomagnetic analyses) features, from which they derive a number of conclusions: 1) the pre-evaporitic Gello Composite Section can be subdivided into four intervals, each one typified by peculiar paleoenvironmental conditions in terms of paleobatimetry and/or physicochemical characters of the water. An overall deepening-upward trend characterizes the studied section, starting from the base up to its middle-upper part, when a decrease of water depth likely occurred, thus heralding the evaporitic deposition recorded by the gypsum at the top of the section; 2) the combination of two major climate sensitive records (because the investigated deposits manifest no evident lithological cyclicity), i.e. the fluctuations of CaCO 3 and faunistic contents (benthonic and planktonic foraminifera), has highlighted the presence of 18 precession cycles and the influences of the lower frequency astronomical periodicities. Particularly, the distribution of the genus Bolivina and the Shannon-Weaver index curve are key records to unravel high frequency cyclicity, whereas the distribution of planktonic taxa seems to be controlled also by the obliquity periodicity; 3) the key bioevents characterizing some of the astronomically calibrated preevaporitic Messinian sections, such as Abad Composite and Falconara sections, have been recognized also in the Gello Composite Section. These bioevents along with the age of the C3An.1r/C3Ar.1n magnetostratigraphic boundary have provided age constraints for the astronomical calibration of the section with the standard curves of the astronomical periodicity; 4) the beginning of the marine sedimentation in the Volterra basin aged at Ma; and 5) the pre-evaporitic marly sedimentation occurred between Ma and Ma. As a consequence, the onset of evaporitic phase related to the Messinian Salinity Crisis in the Volterra Basin and in others Mediterranean type-successions is isochronous. 74

76 THE MIOCENE/PLIOCENE BOUNDARY: CYCLOSTRATIGRAPHY AND BIOSTRATIGRAPHY FROM CAVA SERREDI SECTION (FINE BASIN, TUSCANY-ITALY) F. RIFORGIATO, L.M. FORESI, M. ALDINUCCI, G. SALVATORINI, R. MAZZEI and F. SANDRELLI. Dipartimento di Scienze della Terra, Università di Siena, Via Laterina 8, Siena, Italy According to the recent ratification the Miocene/Pliocene Global Boundary Stratotype Section and Point (GSSP) is located at the base of the Trubi Formation of the Eraclea Minoa Section (5 precessional cycles below the Thvera Magnetosubchron), and it has an astrochronological age of 5.33 Ma. As a consequence of this ratification, the M/P conformable boundary recorded within Tuscan sections, needs to be both reconsidered through a multidisciplinary approach based on high resolution stratigraphy and compared with the most significant Mediterranean succession of the same age. In Tuscany, the M/P boundary is well exposed at Cava Serredi Section in the Fine River Basin, and has been traditionally correlated to the surface which marks the abrupt change in depositional setting between open marine fines and underlying lacustrine deposits (post-evaporitic phase). This abrupt change has been related to the flooding of the Mediterranean after salinity crises; and was clearly recognizable in all over basin both in land and deep-marine sections. The succession has been detailed described, measured and sampled in the course of Cofin Project (2003) aimed at the reconstruction of a high-resolution stratigraphic framework for the Messinian. It covers a sequence referable to the topmost Messinian (150 m thick) and lower Pliocene (about 22 m thick). In the Messinian part a Lago Mare assemblage, other Paratethyan brackish ostracods and rare benthic foraminifera (Ammonia beccarii tepida, Bolivina paralica and small Discorbidae) are present, indicating oligohaline to mesohaline water conditions. In the Pliocene part the rich and well diversified assemblages document a rapid drowning with a depositional environment which reached bathymetry referable to the outer neritic-upper epibathyal zone. The main bioevents recorded within the most significant and astrochronologically calibrated lower Pliocene Mediterranean sections, have been recognised also in the Pliocene fines of Cava Serredi. Specifically, the main planktonic events recognised are: 1) two short sinistral influxes of Neogloboquadrina acostaensis; 2) the acme interval of Globigerina nepenthes; 3) the common occurrence of Globorotalia scitula. Some benthic foraminiferal events recognised are: 1) the presence of Buliminella inauris in the basal samples of the Pliocene succession and its absence upward; 2) the occurrence of Globocassidulina subglobosa and Oridorsalis stellatus; 3) the occurrence of Anomalinoides helicinus. Since the investigated deposits manifest no evident lithological cyclicity, others records have been used to recognize astronomical periodicity, like: CaCO 3 content and faunistic fluctuations (Globigerinoides spp., Turborotalita quinqueloba and G. bulloides). Particularly, insolation maxima-precession minima correspond to i) minima in CaCO 3 content and in the distribution patterns of Turborotalita quinqueloba and G. bulloides; ii) maxima in the distribution pattern of Globigerinoides spp. As a result, 4 precessioncontrolled cycles have been recognised in the open marine deposits. Based on this study, it follows that the base of the Pliocene deposits exposed in the Cava Serredi is coeval with M/P boundary, as formally ratified at Eraclea Minoa Section. 75

77 THE SICILIAN RECORD OF THE MESSINIAN SALINITY CRISIS: A SEQUENCE-STRATIGRAPHIC APPROACH M. ROVERI 1, S. LUGLI 2, V. MANZI 1 and B.C. SCHREIBER 3 1 Dipartimento di Scienze della Terra, Università di Parma, Via G.P. Usberti, 157/A, Parma, Italy 2 Dipartimento di Scienze della Terra, Universitá di Modena e Reggio Emilia, Piazza S. Eufemia 19, Modena, Italy. 3 Department of Earth and Space Sciences, University of Washington, P.O. Box , Seattle WA 98195, USA Field studies carried out in the last years in Sicily, a key area for the comprehension of the Messinian salinity crisis (MSC), show that the classic stratigraphic models for this complex geologic event (Ogniben, 1957; Decima and Wezel, 1973; Garcia-Veigas et al., 1995; Rouchy and Caruso, 2006) need to be reconsidered. Albeit forced by external climatic factors, the distribution in space and time of Messinian evaporitic and clastic deposits was obviously controlled by the structural evolution of the Sicily foreland basin. Detailed facies analysis allowed us to reconstruct a sequence stratigraphic framework based on the recognition and correlation of genetically-related units bounded by key surfaces. Two large-scale, composite depositional sequences can be recognized, separated by a sequence boundary corresponding to the intra-messinian unconformity. Smaller scale depositional sequences probably related to high-frequency climatic cycles are superimposed to the main sequences; the latter roughly correspond to the Lower and Upper Evaporitic cycles of Butler et al. (1995), from which they significantly differ for both internal organization and absolute age of key events. The first phase of the MSC corresponds to the highstand systems tract (HST) of the lower sequence as suggested by the progressive upward facies change and thickness reduction of individual evaporitic cycles (Lugli et al., 2006; Roveri et al., 2006); primary selenites of the Gessi di Cattolica Fm. (Lower Gypsum) started to deposit since around 5.96 Ma in shallow, semi-closed basins formed in both compressive and extensional tectonic settings, respectively above the orogenic wedge and on the Hyblean foreland area, while in the main foredeep (Caltanissetta basin) only organic-rich, barren shales with interbedded carbonate (dolomitic) layers accumulated. A very complex unit comprising resedimented gypsum, evaporitic micritic limestone (Calcare di Base - CdB) and halite was deposited in the main foredeep between 5.6 and 5.55 Ma during a short but strong tectonic pulse, probably coupled with a moderate to high-amplitude sea-level fall. This syn-tectonic unit accumulated only in the Caltanissetta basin, characterized by an articulated, structurally controlled topography, while the Lower Gypsum underwent subaerial exposure and erosion; the unit records the acme of the MSC, when the connections with the Atlantic Ocean were severely reduced, leading to the accumulation of huge volumes of evaporites in deep Mediterranean basins. Besides tectonics, the MSC paroxysmal phase was likely triggered by sea-level lowerings associated to the TG12 and TG14 isotopic stages. The unit is here interpreted as a falling sea-level systems tract (FSST) bounded on top by a diachronous subaerial unconformity. According to this reconstruction the CdB has neither genetic nor stratigraphic relationships with the Lower Gypsum, as usually envisaged in classic models; similarly, 76

78 M. ROVERI, S. LUGLI, V. MANZI and B.C. SCHREIBER the resedimented gypsum is here considered to fully postdate the primary selenite of the Gessi di Cattolica Fm.; it follows that the term Lower Gypsum, currently used for both primary and resedimented gypsum facies, is worth to generate stratigraphic confusion. As a matter of fact, the CdB is present invariably at the base or in the lower part of successions comprising resedimented gypsum, halite and selenite, the latter belonging exclusively to the Upper Gypsum (Gessi di Pasquasia Fm.) and being commonly and erroneously attributed to the Lower Gypsum. The CdB is normally represented by both autobrecciated and resedimented facies and is here interpreted as the product of penecontemporaneous dismantling through dissolution, autobrecciation and/or gravitational processes of small carbonate platforms developed in very restricted waters above actively growing structural highs within or at the borders of the main foredeep basin. Continuous uplift caused the progressive narrowing and exposure of these platform tops and the steepening of the frontal slope, promoting increasingly active destructive processes over constructional ones. Thick halite accumulated in deeper and more subsident depocenters; the exceptionally-high accumulation rates of salt led to fast basin infill up to local subaerial exposure. The desiccation surfaces found in the upper part of halite bodies at Realmonte (Lugli et al., 1999) and Racalmuto probably formed at the lowest relative sea-level and is here correlated to the FSST upper boundary. The FSST lower boundary is a surface (basal surface of forced regression - BSFR) corresponding to the sea-floor profile at the beginning of the relative sea-level fall; it can be placed, according to the position along the palaeodepositional profile, at the sharp transitions from Tripoli or euxinic shales to either the CdB, the resedimented gypsum or the halite. This surface can be locally unconformable due to subaqueous erosional processes associated to gravity flow and mass wasting; as a consequence, a stratigraphic hiatus of variable amplitude can be eventually recognised across this lithostratigraphic boundary, thus explaining the different basal age obtained for the CdB (Butler et al., 1995) and usually associated to a diachronous onset of the MSC due to local factors (Rouchy and Caruso, 2006). The sequence boundary is represented by a subaerial unconformity in uplifted areas and by its correlative conformity in deeper basins; according to different sequencestratigraphic models, the correlative conformity can be traced either to the base (Posamentier et al., 1988, 2 in Fig. 1) or to the top (Hunt and Tucker, 1992; 1 in Fig. 1) of the FSST. In basins where salt did not accumulate the FSST top corresponds to the vertical transition from clastic gypsum to shale and selenite belonging to the Upper Gypsum unit. Wherever the FSST has to be placed, in the Lower or in the Upper Sequence, the Upper Gypsum unit or, locally, the uppermost parts of the halite unit are found above its top. The Upper Gypsum is characterized by a rhytmic alternation of shale and shallow water selenitic and laminar gypsum (Gessi di Pasquasia Fm.) with an aggradational stacking pattern, testifying to a phase of overall but slow relative base-level rise, a typical signature of the lowstand systems tract (LST). A change to a retrogradational stacking pattern, best seen in wedge top basins dominated by clastic, fluvio-deltaic systems, and the concurrent appearance of faunal assemblages indicating a progressive dilution of surface waters (Lagomare stage), suggest that the upper part of this unit and the Arenazzolo Fm. represent a transgressive systems tract (TST); cyclostratigraphic considerations indicate an age of Ma for the LST-TST transition. The sharp base of the open marine Trubi Fm. can be interpreted as the maximum flooding surface 77

79 M. ROVERI, S. LUGLI, V. MANZI and B.C. SCHREIBER (MFS) of the upper sequence, marking the return to normal connections with the Atlantic Ocean at 5.33 Ma. This model helps to elucidate the complex stratigraphic relationships developed in a very active geodynamic setting by hybrid depositional systems, leading to the refinement and calibration of ideas first proposed by Mario Grasso and coworkers (Pedley and Grasso, 1993; Butler et al., 1995). The key point of our reconstruction is the recognition of the syntectonic character of the CdB-resedimented gypsum-halite FSST unit and its actual relationships with the Lower Gypsum. The erosional surface cutting the top of both the Lower Gypsum and the CdB in the inner foredeep or wedge top depozones, does not necessarily mean that the two deposits were coeval and genetically related as usually thought. The ongoing deformation and the competition between fast aggradation of salt and basin subsidence accounts for the development within the FSST of progressive unconformities and local erosional surfaces, leading to the very complex and highly variable lithostratigraphy characterizing this unit. Our stratigraphic model opens the way to a new and more comprehensive scenario of the MSC, allowing the recognition of the correspondence between the Messinian events recorded in the Sicilian and in the deep Mediterranean basins, ruling out models envisaging an additional sequence boundary at the base of the Arenazzolo Fm., interpreted as the deep basin desiccation phase (Clauzon et al., 2005). On the contrary, the classic tripartite deep Mediterranean basin stratigraphy appears a perfect equivalent of the Caltanissetta basin FSST (Lower Evaporites comprising clastic gypsum and halite), LST and TST (Upper Evaporites). According to this view, the first phase of the MSC has no evaporitic equivalents in the deep basins, as observed in the Caltanissetta basin and already proposed for the Apennine foredeep (Roveri et al., 2001; Manzi et al., 2007). Fig. 1 Stratigraphic model for the Messinian of Sicily and correlation with Apennine and deep Mediterranean successions. Sequence stratigraphy according to (1) Hunt and Tucker (1992) and 2) Posamentier et al. (1988). Abbreviations: Ar, Arenazzolo Fm.; CdB, Calcare di Base; gc, Gessi di Cattolica Fm.; gp, Gessi di Pasquasia Fm.; Ha, halite;lg, gypsum laminite; r, pre-evaporitic reefs; rg, resedimented gypsum; su, subaerial unconformity; Ter, Terravecchia Fm.; T-Ml, Tellaro Fm- Marly limestones. Mediterranean seismic reflectors from Lofi et al. (2005) and Bertoni and Cartwright (2007). 78