Tyrrhenian Sea tephrochronology of the oxygen isotope record for the past 60,000 years

Abstract

A chronology of the marine oxygen isotope record of the past 60 ka is proposed by correlating eight marine ash-layers with terrestrial volcanic deposits, dated by the 14C and/or K Ar methods. Detailed oxygen isotope analyses were made on the planktonic foraminifera of three cores collected in the central Tyrrhenian Sea. The origin of the ash-layers was determined by major and trace elements analyses. Then the major pyroclastic terrestrial deposits were sampled, and analysed in order to provide land-sea correlations. Two ash-layers occurred during the warm event that followed the first step of the deglaciation, and which was dated at 12.6±0.5 ka B.P. Another ash-layer is present near the last glacial maximum that we have dated at 17.5±0.3 ka B.P. During isotopic stage 3, five ash-layers were recognized and dated, which allowed us to assign ages to the isotopically light oxygen peaks (warmer interstadials) at 31±1.5 ka and 33.4±1.6 ka (Denekamp), at 37.5±2 ka (Hengelo), and successively at 49±2 ka, 52.4±2.2 ka, 57±2.2 ka and 60.5±2.2 ka (Moershoofd complex).