DISTRIBUTION OF STABLE ISOTOPES IN SURFACE SNOW ALONG THE ROUTE OF THE 1990 INTERNATIONAL TRANS-ANTARCTICA EXPEDITION

This paper presents the distribution of average deltaD and deltaO-18 values for the top 1 m of surface snow for a large area of Antarctica. The samples were collected on the 1990 International Trans-Antarctica Expedition which crossed the continent from the northern tip of the Antarctic Peninsula to Mirny Station. The empirical relationships between the isotopes, temperature and elevation are computed. The slopes of deltaD with respect to the surface temperature for the segments west (Patriot Hills-Vostok) and east of Vostok (Komsomolskaya-Mirny) are not significantly different to that observed between Dumont d'Urville and Dome C (Lorius and Merlivat, 1977) which are often used to interpret deep ice-core isotopic profiles. There is, however, a noticeable shift between the two regression lines with, for a given temperature higher isotopic values west of Vostok. The deuterium excess values (d = deltaD - 8 x deltaO-18) increase sharply at 3000 m a.s.l. on the plateau, confirming the results of Petit and others (1991).