SEDIMENTOLOGICAL INVESTIGATIONS ON A LATE QUATERNARY LACUSTRINE CORE FROM THE LAGACCIONE CRATER (CENTRAL ITALY) - PALEOCLIMATIC AND PALEOENVIRONMENTAL INFERENCES

The Lagaccione crater is a Late Pleistocene explosive centre of the Vu lsini volcanic district (42 degrees 34'N, 11 degrees 51'E, Central Ita ly); it was the site of lacustrine sedimentation until the last centur y, when it was completely dried out For agriculture. With the aim of o utlining long-term variations of past climates and environments, sedim entological investigations were carried out on a 49.5 m long sequence cored in the lake bed centre. According to biostratigraphical consider ations, radiocarbon datings and tephrochronology the lacustrine record spans approximately the last 100 ka. It consists of noncalcareous sil ty sediments; fluctuations of mineralogical and geochemical characteri stics with depth indicate that the biological productivity and the che mical leaching in the catchment area varied considerably on a regional scale as a consequence of three main temperate and/or wet phases, alt ernating with dry and/or cold climatic conditions. Considerations of s ediment grain size and organic matter quality permit a schematic descr iption of the evolution of the local palaeoenvironmental framework. (C ) 1998 INQUA/Elsevier Science Ltd. All rights reserved.