Arid and humid phases in central Italy during the Late Pleistocene revealed by the Lake Trasimeno ostracod record

摘要

AbstractA multiproxy approach in a sediment core from Lake Trasimeno has been used to reconstruct the climate history of central Italy during the Late Pleistocene to Early Holocene period (ca. 47,000–9,000calyr B.P.). Ostracod assemblages and sedimentological data (lithology and carbonate content) have been used to infer past hydrological changes in the area. Ostracods were analyzed throughout the core using diversity indexes and multivariate statistic analyses (Cluster and PCA). Three main associations linked to lake level and salinity variations were recognized: 1) theC. torosaassociation, indicating permanent lacustrine conditions with high lake levels and low salinities; 2) theS. aculeataassociation, linked to very shallow/temporary waters with higher salinity conditions; and 3) theS. aculeata-E. mareoticaassociation pointing to temporary water conditions and the highest salinities. Furthermore, the presence ofC. fuscataandL. blankenbergensisduring wide parts of the Late Pleistocene indicates temperatures lower than present days. Alternations of these three ostracod associations compares well with the oxygen isotope curve from Greenland (NGRIP) and are thus interpreted as climatically driven. At the Holocene transition (Termination 1), the ostracod associations indicate a delay in the increasing warming and humidity with respect to the NGRIP temperature record.展开▼