Volcanic synchronisation between the EPICA Dome C and Vostok ice cores (Antarctica) 0–145 kyr BP

摘要

This study aims at refining the synchronisation between the EPICA Dome C(EDC) and Vostok ice cores in the time interval 0–145 kyr BP by using thevolcanic signatures. 102 common volcanic events were identified by usingcontinuous electrical conductivity (ECM), di-electrical profiling (DEP) andsulfate measurements while trying to minimize the distortion of theglaciological chronologies. This is an update and a continuation of previousworks performed over the 0–45 kyr interval that provided 56 tie points tothe ice core chronologies (Udisti et al., 2004). This synchronisation willserve to establish Antarctic Ice Core Chronology 2012, the next synchronisedAntarctic dating. A change of slope in the EDC-depth/Vostok-depth diagram isprobably related to a change of accumulation regime as well as to a changeof ice thickness upstream of the Lake Vostok, but we did not invoke anysignificant temporal change of surface accumulation at EDC relative toVostok. No significant phase difference is detected between the EDC andVostok isotopic records, but depth shifts between the Vostok 3G and 5G icecores prevent from looking at this problem accurately. Three possiblecandidates for the Toba volcanic super-eruption ~73 kyr ago aresuggested in the Vostok and EDC volcanic records. Neither the ECM, DEP northe sulfate fingerprints for these 3 events are significantly larger thanmany others in the records.