Millennial- to centennial-scale palaeoclimatic variations during Termination I and the Holocene in the central Mediterranean Sea

摘要

We compared palaeoclimate proxy records of two deep-sea sediment cores from the Tyrrhenian Sea to provide new insights into the climate variability in the Mediterranean basin during Termination I and the Holocene. High-resolution sequences of Globigerina bulloides and Globigerinoides ruber oxygen stable isotope analyses and planktonic foraminifera abundances for cores BS7937 and BS7938 are presented here. The sedimentation rates (on average 18 cm/ky for BS7937 and 25 cm/ky for BS7938) calculated for these cores are among the highest recorded in the Tyrrhenian Sea and the sampling resolution of core BS7938 provides the first centennial-scale study available for the Holocene in this area. At least seven cold episodes, with an average duration of 650 years (from 400 to 1000 years), have been clearly recognised in the record of the last 12 ky in the planktonic foraminiferal and δ~(18)O profiles of both cores. The timing and intensity of such coolings is in good agreement with others previously identified in the Mediterranean basin and this testifies to their wide distribution in an area previously thought to be characterised by Holocene climatic stability. This environmental variability has also been further highlighted by the revised biozonation applied to the relative abundances of the main planktonic foraminifera species recognised in the south Tyrrhenian Sea.