Abrupt environmental oscillations during the Early Weichselian recorded atLago Grande di Monticchio, southern Italy

This study presents multi-proxy data from a new core from Lago Grande di Mo nticchio (Italy) extending back to about 100,000 calendar years BF. The tim e scale of this record is independent from deep-sea and ice-core chronologi es and has been established from a combination of varve counts and high-res olution sedimentation rate calculations based on microscopic sediment inves tigation. This paper focuses on environmental variability between 100,000 a nd 65,000 calendar years BP. Several abrupt cold periods have been recognis ed and correlated to other terrestrial as well as to ice-core and deep-sea records. The longest of the Monticchio cold phases corresponds to Marine Is otopic Stage 5b and lasted from ca 87,000 to 84,000 calendar years BP. Two shorter events (about 1000 years long) occurred during the transition from interstadial to full glacial conditions between 79,000 and 75,000 calendar years BP. The increased frequency of cold events during this time interval probably indicates a higher degree of climatic instability in periods of ma jor changes. Dating discrepancies between Monticchio, GRIP, and deep-sea ch ronologies range between a few hundred to a few thousand years. However, th ese differences in dating are not constant but vary significantly for diffe rent sections of the records. Nevertheless, the good match of environmental fluctuations at Monticchio with atmospheric variability at the Greenland S ummit as well as variations in the oceanic circulation pattern suggests a c lose link of the Mediterranean to the Atlantic climate regime. (C) 2000 Els evier Science Ltd and INQUA. All rights reserved.