STRATIGRAPHIC ARCHITECTURE OF THE SALENTO COAST FROM CAPO D'OTRANTO TO S.MARIA DI LEUCA (APULIA, SOUTHERN ITALY)

The Cretaceous to Quaternary succession of the Apulia Platform cropping out on the eastern coast of the Salento Peninsula shows a special stratigraphic architecture. Whereas on the platform top, i.e. on the Salento Peninsula proper, the succession is at most a few tens of metres thick and is punctuated by unconformities, on the margin and slope of the platform, along the present-day eastern coast of the peninsula, several carbonate systems are laterally disposed and grafted one upon the other. Three of these systems are clinostratified and include well developed reef tracts of Priabonian, early Chattian and early Messinian age. The geologic conclusion of our study is that, since the Late Cretaceous, the eastern coast of the Salento Peninsula grossly coincided with the margin of the Apulia Platform. This paleogeographic element acted as a foreland horst and registered important geodynamic events related to the growth of the adjacent Hellenide and Apennine thrust belts. During the last 60 m.y., the horst carapace was constantly near sea level and sediments were mainly accommodated and preserved on the deep margin and slope of the platform.&nbsp

Stable oxygen and carbon isotope ratios of Globigerinoides obliquus of quantitative range chart of the ostracodes in the Pliocene-Pleistocene interval of ODP Hole 107-654A

Deep-water benthic ostracodes from the Pliocene-Pleistocene interval of ODP Leg 107, Hole 654A (Tyrrhenian Sea) were studied. From a total of 106 samples, 40 species considered autochthonous were identified. Detailed investigations have established the biostratigraphic distribution of the most frequent ostracode taxa. The extinction levels of Agrenocythere pliocenica (a psychrospheric ostracode) in Hole 654A and in some Italian land sections lead to the conclusion that the removal of psychrospheric conditions took place in the Mediterranean Sea during or after the time interval corresponding to the Small Gephyrocapsa Zone (upper part of early Pleistocene), and not at the beginning of the Quaternary, as previously stated. Based on a reduced matrix of quantitative data of 63 samples and 20 variables of ostracodes, four varimax assemblages were extracted by a Q-mode factor analysis. Six factors and eight varimax assemblages were recognized from the Q-mode factor analysis of the quantitative data of 162 samples and 47 variables of the benthic foraminifers. The stratigraphic distributions of the varimax assemblages of the two faunistic groups were plotted against the calcareous plankton biostratigraphic scheme and compared in order to trace the relationship between the benthic foraminifers and ostracodes varimax assemblages. General results show that the two populations, belonging to quite different taxa, display almost coeval changes along the Pliocene-Pleistocene sequence of Hole 654A, essentially induced by paleoenvironmental modifications. Mainly on the base of the benthic foraminifer assemblages (which are quantitatively better represented than the ostracode assemblages), it is possible to identify such modifications as variations in sedimentation depth and in bottom oxygen content

Benthic communities and sedimentary facies recording late Quaternary environmental fluctuations in a Po delta subsurface succession (Northern Italy)

8The upper Quaternary of the Po Delta region consists of thick marine and continental deposits, that accumulated in a strongly subsiding portion of the Apennines Foredeep. These successions record large eustatic and climatic fluctuations, dramatically affecting the depositional dynamics of the area. The paper is focused on the palaeoenvironmental interpretation of a 188 m deep borehole, recently cored through the upper Quaternary succession, in the northeastern portion of the Ferrara Province. This is the deepest continuously cored stratigraphic borehole ever drilled in the Po Delta area. The work integrates sedimentological and palaeontological analysis to produce an interdisciplinary reconstruction of the palaeoenvironmental evolution. Palaeoeontological study was focused on dif¬ferent taxonomic groups, ranging from ostracods to foraminifers and mollusks. Several discrete fos¬sil associations were described for each taxonomic group, typifying various depositional environ¬ments, such as freshwater (F), brackish (B), marine (M), and reworked-transported (R) associations. In the marine sediments, four foraminiferal groups (Ma, b, d, e) and varying ostracod and mollusk associations record important salinity and water depth variations. The depositional history of the succession ranges from more than 200,000 yr ago to the present, as suggested by the regional strati-graphic correlation and the 14C dating of the younger portion of the succession. The stratigraphic column is dominated by two thick continental bodies, intercalated by three paralic and marine inter¬vals, corresponding to the last two interglacial highstand phases and to the Holocene post-glacial interval. The two continental units consists of lower alluvial plain deposits, showing scattered fresh¬water ostracod and mollusk faunas, capped by cold-climate coarse sands, deposited in middle allu¬vial plain environments, under lowstand conditions. The lower portion of the borehole records two marine transgressive pulses, developed during interglacial highstand times. In the middle and upper portion of the succession, two transgressive-regressive cycles show a similar asymmetric architectu¬re, with a thin, deeping upward basal unit, followed by a thick regressive portion consisting of pro-delta muds, in turn overlain by delta front sands, with reworked microfossils and storm concentra¬ted mollusk coquinas. The evolutionary trend of the entire succession can be well correlated with the late Quaternary sea level variations, suggesting that the eustatic forcing played a major role in the shaping of the analysed depositional history, even in a tectonically active foredeep area. keywords. Benthic communities, late Quaternary, Po Delta.nonemixedBONDESAN M; CIBIN U; COLALONGO M; PUGLIESE N.; STEFANI M; TSAKIRIDIS E; VAIANI S; VINCENZI SBondesan, M; Cibin, U; Colalongo, M; Pugliese, Nevio; Stefani, M; Tsakiridis, E; Vaiani, S; Vincenzi, S

Note Illustrative della Carta Geologica D’Italia alla scala 1:50.000 foglio 220 Casalecchio di Reno

I rilievi geologici eseguiti per la realizzazione di questo foglio sono stati svolti alla scala 1:10.000 negli anni ‘80 nell’ambito del progetto “Carta geologica dell’Appennino emiliano-romagnolo alla scala 1:10.000” della Regione Emilia-Romagna e, a partire dal 1991, revisionati per l’allestimento alla scala 1:50.000. Gran parte del foglio ricade nella provincia di Bologna mentre la porzione più occidentale ricade nella provincia di Modena ed è compreso tra le valli del Panaro a ovest e del Reno a est. Il limite orientale attraversa il centro di Bologna mentre quello occidentale passa per Vignola (MO). Il limite meridionale attraversa la periferia nord di Sasso Marconi (BO), passando poco a nord di Savigno (BO), mentre quello settentrionale attraversa Castelfranco Emilia (MO). Il foglio è attraversato circa a metà dal margine appenninico-padano che segna il limite, in questo caso orientato circa est-ovest, tra il settore appenninico a sud e la Pianura Padana emiliano-romagnola a nord. Per la cartografia e la descrizione delle successioni marine che costituiscono l’ossatura del settore appenninico è stato seguito il criterio litostratigrafico (CNRCCGG, 1992; SALVADOR, 1994). Sulla base delle recenti indicazioni in materia dettate dal Servizio Geologico Nazionale, per la cartografia e la descrizione dei terreni continentali quaternari della pianura e delle valli intramontane si sono utilizzate le Unconformity Bounded Stratigraphic Units (SALVADOR, 1987). Per favorire le correlazioni alla scala della catena, le successioni riconosciute sono state riunite in grandi insiemi (Liguridi, Successione epiligure, Successione post-evaporitica del margine padano-adriatico) sul cui significato esiste un generale accordo alla scala della catena. La legenda della carta è organizzata secondo l’ordine di sovrapposizione geometrica riconoscibile sul terreno, mentre la descrizione delle unità stratigrafiche nelle presenti note (cap. IV) segue l’ordine di sovrapposizione geometrica per quanto riguarda le Liguridi e l’ordine cronologico, dalla più antica alla più recente, per quanto riguarda i terreni non strutturati in unità tettoniche (Successione epiligure e Successione post-evaporitica del margine padano-adriatico)

Note Illustrative del Foglio Geologico Ufficiale 187 Codigoro 1:50.000

Carta Geologica di Sintesi al 1/50.000 del progetto nazionale CARG, di sui Marco Stefani è stato direttore di rileamento e coordinator