The Apennine chain, in peninsular Italy, is characterized by the presence of numerous intramontane basins of extensional tectonic and volcano-sedimentary origin, hydrographically poorly connected. Their basin fill in Quaternary time is composed of alluvial-lacustrine sequences. Rich and diverse freshwater mollusc assemblages are found in basins such as Liri, Sulmona, Acerno, Vallo di Diano, Mercure, Noce and Venosa Basins. New lithostratigraphic and paleontologic analyses on basin fills and mollusc assemblages, integrated with published isotopic, tephro-, magneto-, palyno-stratigraphic and biochronologic data, permit to recognize a common climate-driven sedimentation pattern, and to precisely date assemblages to the Middle-earliest Late Pleistocene. Recognised interglacials are dominated by fine carbonate lake sedimentation and by well preserved high specific diversity assemblages of gastropods and bivalves, both recording well-oxygenated environments. The fauna is characterized by the wide occurrence of an extinct species of the thermophilous prosobranch Tanousia. Conversely, detected glacials recorded phases of lake overfilling and coarse-grained fan delta progradation, with low diversity fauna with prevailing flowing-water bivalve Dreissena. Despite the poor hydrographical connectivity among basins, homogeneity in their paleontologic and sedimentologic character, along with external chronological constraints, permits an inter-basins correlation. In particular, since the mollusc paleocommunity structure, as for taxonomic and distribution pattern in space and time, is uniform throughout the basins, the related paleoecologic and paleoclimatic signals can be hypothesized as a common feature for the central-southern Apennines during some Middle Pleistocene cold and warm phases. Moreover, the Middle-Late Pleistocene faunal composition has a modern character, quite different from that of the endemic and archaic Villafranchian assemblages of central Italy.
CLIMATIC, TECTONIC AND VOLCANIC CONTROLS ON ALLUVIAL-LACUSTRINE SEDIMENTATION AND FRESHWATER MOLLUSC ASSEMBLAGES IN MIDDLE-LATE PLEISTOCENE INTRAMONTANE BASINS OF ITALY
Marco Mancini
2012
Abstract
The Apennine chain, in peninsular Italy, is characterized by the presence of numerous intramontane basins of extensional tectonic and volcano-sedimentary origin, hydrographically poorly connected. Their basin fill in Quaternary time is composed of alluvial-lacustrine sequences. Rich and diverse freshwater mollusc assemblages are found in basins such as Liri, Sulmona, Acerno, Vallo di Diano, Mercure, Noce and Venosa Basins. New lithostratigraphic and paleontologic analyses on basin fills and mollusc assemblages, integrated with published isotopic, tephro-, magneto-, palyno-stratigraphic and biochronologic data, permit to recognize a common climate-driven sedimentation pattern, and to precisely date assemblages to the Middle-earliest Late Pleistocene. Recognised interglacials are dominated by fine carbonate lake sedimentation and by well preserved high specific diversity assemblages of gastropods and bivalves, both recording well-oxygenated environments. The fauna is characterized by the wide occurrence of an extinct species of the thermophilous prosobranch Tanousia. Conversely, detected glacials recorded phases of lake overfilling and coarse-grained fan delta progradation, with low diversity fauna with prevailing flowing-water bivalve Dreissena. Despite the poor hydrographical connectivity among basins, homogeneity in their paleontologic and sedimentologic character, along with external chronological constraints, permits an inter-basins correlation. In particular, since the mollusc paleocommunity structure, as for taxonomic and distribution pattern in space and time, is uniform throughout the basins, the related paleoecologic and paleoclimatic signals can be hypothesized as a common feature for the central-southern Apennines during some Middle Pleistocene cold and warm phases. Moreover, the Middle-Late Pleistocene faunal composition has a modern character, quite different from that of the endemic and archaic Villafranchian assemblages of central Italy.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
