Here we present evidence that marine organic matter Δ13C measurements can closely reproduce the Vostok ice core CO2 record and, in addition, can be used to evaluate the absolute Vostok chronology and the transfer of that chronology between the marine and terrestrial realm. Our data supports recent speculations that the base of the Vostok ice core (2755 m) is still within oxygen isotope stage 7, in agreement with recent orbitally-tuned ice core chronologies. ¿ American Geophysical Union 1996