Abstract:

Mineral phase constituents of lacustrine deposits from the Fildes Peninsula of King George Island,Antarctica,are quite similar each other,but different in their contents. The outstanding feature of deposits is of great proportion of non crystalline matter and less in the species of crystalline minerals. Plagioclass (labradorite) is main phase in primary minerals of source rock with less quartz. Secondary minerals are mostly the clay minerals. K bearing minerals are completely lack in deposits. Obviously,all these can be assigned to being the mineralogical characteristics of meta basic rock source and show close genetic and inherited relationship in mineral phase constituents between lacustrine deposits and meta basic volcanic rock spreaded broadly at the peninsula. Among clay minerals,montmorillonite is dominant and kaolinite is less. There is a little difference in chemical compositions between lacustrine deposits and volcanic rock. The constituents of mineral phases change less with grain size. All these clearly prove that physical weathering of the parent rock is much stronger than the chemical weathering. The lacustrine deposit layer and glacial drift layer can be distinguished by the relation curves between the contents of kaolinite or calcite and ages,and their boundary ages are basically consistent with corresponding measured ages.