南极菲尔德斯半岛古海蚀龛沉积的古环境记录

在西南极菲尔德斯半岛长城站地区发现有大量古海蚀龛 ,龛内保存有完整沉积剖面 ,通过对其中一个沉积剖面的粒度特征及元素组成的分析 ,确认该剖面是后期的湖相沉积 ,并据此恢复了距今 460 0年以来该地区古环境演化历史。结果表明 ,距今 40 0 0— 30 0 0年长城站区地表岩石化学风化作用较强烈 ,处于一个相对温暖的时期 ,这与湖泊沉积物、海洋沉积物等古环境记录载体的研究结果是一致的 ,证明古海蚀龛沉积可以作为研究南极无冰区和冰缘地区古环境演化历史的一种新的地质载体。

PALAEOENVIRONMENTAL RECORDS FROM PALAEOGOE SEDIMENTS ON FILDES PENINSULA, ANTARCTICA

A great deal of palaeogoes have been found in the area around the Great Wall Station located on Fildes Peninsula in west Antarctica, in which intact sedimental sections are preserved. By the analysis of the grain size characteristics and elemental composition in sediments collected from one of those sections, we can affirm that the sedimental section is composed of lake sediments , by which the evolutional history of paleoenviroment in this area since 4600aBP has been reconstructed. The results indicate that chemical weathering of rocks on the earth surface in the Gread Wall Station area is relatively strong from 4000 to 3000aBP, which is suggestive of a comparatively warm period, and this warm period is also imprinted in some sedimental records such as lake and marine sediments. It is proved that palaeogoe sediments can be regarded as a new geological carrier by which we can research palaeoenvironmental evolution history in the ice-free and periglacial area, Antarctica.