Tephrochronology of the 100 ka lacustrine sediment record of Lago Grande di Monticchio (southern Italy)

The results of a tephrochronological study on 340 distal tephra layers intercalated within 72.5 m of sediments in Lago Grande di Monticchio (southern Italy) are outlined. This maar lake provides a continuous, high temporal resolution record of climate and environmental change for the last 100 kyr. From a total of 340 intercalated tephra layers, 42 prominent tephras have been selected for detailed microscopic, chemical and chronological investigations in order to obtain a second chronological fundament complementary to the varve-supported sedimentation rate chronology providing in combination a high precision timescale of this important palaeoclimatic record. All these tephra layers have been correlated with highly explosive eruptions of Central and South Italian volcanoes. The historically dates, radiometric, radioisotopic and interpolated ages of 26 correlated tephra events and direct laser 40Ar/39Ar dates for Monticchio tephra layers are consistent with ages of tephra deposition provided by the independent sedimentation rate chronology of Monticchio sediments with a mean deviation of similar to5%. Aside from its tephrochronological purpose, the study of tephra layers in the Monticchio sediments also contributes to a better knowledge of the explosive history of Italian volcanoes and the dispersal of erupted tephra material. (C) 2004 Elsevier Ltd and INQUA. All rights reserved.