VOSTOK (ANTARCTICA) ICE CORE - ATMOSPHERIC CHEMISTRY CHANGES OVER THE LAST CLIMATIC CYCLE (160,000 YEARS)

A 2083 m deep ice core from Vostok Station (East Antarctica) has been used for a comprehensive study of all major ions originating from aerosols deposited over the last climatic cycle as depicted from the isotopic composition of the ice. Concentration profiles confirm that both marine and terrestrial aerosol inputs were higher during cold climatic conditions than during the Last Interglacial and the Holocene stages. High concentration peaks (up to 5 and 30 times the Holocene values of marine and terrestrial contents, respectively) are in particular observed during the very cold climate characterizing the end of the penultimate glacial age and the Last Glacial Maximum which terminated around 15 ka B. P. As opposed to marine and terrestrial inputs, acidic gas-derived impurity concentrations (HNO//3, H//2SO//4) remain relatively stable over the whole climatic cycle. In particular there is no correlation between observed H//2SO//4 fluctuations and the isotope-temperature profile. The mineral acid contribution represents a large part (over 50%) of ice impurities deposited during interglacial periods. Additional aspects of the subject are discussed.