东南极拉斯曼丘陵区的冰川作用

拉斯曼丘陵在渐新世已被冰盖覆没，晚渐新世冰盖厚度最大，自中新世开始，冰盖逐渐减薄后退，但该丘陵仍为冰盖占据。更新世冰川作用规模不及第三纪。１８ｋａＢ．Ｐ．该丘陵区覆冰厚度超过１７０ｍ，冰盖前缘仅增厚３０ｍ左右。冰盖后退出露基岩约在１０．０ｋａＢ．Ｐ．前后，自９．４１～６．５ｋａＢ．Ｐ．，冰川以２～３ｍ／ａ的速率后退，岛屿区全部出露；自６．５～５．０ｋａＢ．Ｐ．，冰川后退速率减为１．０～１．５ｍ／ａ，丘陵区裸露５０％以上；约自５．０ｋａＢ．Ｐ．开始，丘陵区几乎全部出露，冰川冰盖范围与今基本相同。

RESEARCH ON THE GLACIATION OF THE LARSEMANN HILLS, EAST ANTARCTICA

The Larsemann Hills are a series of gneiss islets and peninsulas extending into Prydz Bay, between the Amery Ice Shelf and the Sorsdal Glacier. The hills are ice free and form an area of approximately 200km 2 at 69°21′ -69° 28′ S and 76°00′-76°25′E on the Ingrid Christensen Coast of Princess Elizabeth Land, East Antarctica. The hills had been covered by ice sheet as early as Early Oligocene, and the ice sheet was the thickest in the Late Oligocene. Since the Miocene, ice sheet began to be thinner and retreat but covered the hills also. The glaciation scale of the quaternary is far inferior to the Tertiary. The thickness of ice sheet exceeds 170m and the margin thickens about 30 km at 18 ka B.P.. The time of deglaciation and exposed rocky land has been outlined at 10 ka B.P..The islets of the Larsemann Hills were ice free by 6.5ka B.P., and the rate of retreat was 2-3 m/a. By 5.0ka B.P.,50% of the hills were exposed and ice retreated at 1.0-1.5m/a. After 5.0 ka B.P. the rate of retreat did not exceed 0.8-1.0 m/a to its present position.