Investigations of the Oxygen-18 Content of Samples from Snow Pits and Ice Cores from the Filchner-Ronne Ice Shelves and Ekström Ice Shelf

Since 1979–80, isotope studies with oxygen-18 ( 18 O) have been carried out at several snow pits and ice cores near the German Georg-von-Neumayer station (Ekström ice shelf, Atka Bay), as well as from the Filchner-Ronne ice shelves, in the framework of the German Antarctic research programme. The investigations of snow pits on the Filchner-Ronne ice shelves yield a standard deviation for the annual average δ 18 O values of approximately 1‰ over the last five years, and a decrease of δ 18 O with distance from the ice edge of about 1‰ per 50 km. The variation of δ 18 O for stratigraphically matching snow layers from snow pits at the same location in different years is about 0.3‰ on the Filchner-Ronne ice shelves, and 0.8‰ at Georg-von-Neumayer station. The mean annual accumulation rate in the surroundings of Georg-von-Neumayer station was determined to be 34 g cm -2 for the years 1977–81. On the Filchner-Ronne ice shelves the mean annual accumulation rate (1979–83) decreases from 22 g cm −2 at Filchner station to 15 g cm −2 at traverse point T340, located 200 km southeast of Filchner station.