A volcanic marker (92 ka) for dating deep east Antarctic ice cores

Tephra layers recorded in East Antarctic ice enable reliable linking over long distances and, when correlated with well-dated eruptions in the source area, provide absolute ages for improving the accuracy of model-based ice chronology. We used chronostratigraphic information and grain-specific geochemical data (major elements by electron microprobe and trace elements by LA-ICP-MS) to suggest that a tephra layer from the EPICA-Dome C and Dome Fuji ice cores is the distal counterpart of the Mt. Berlin (Marie Byrd Land province, West Antarctica) pyroclastic unit 40Ar/39Ar dated to 92.5±2.0 and 92.2±0.9 ka. Such one-to-one correlation, which is proposed here for the first time for the East Antarctic deep climatic archives, provides independent age constraints for glaciological modelling of core timescales.