关键词: 石英砂;表面结构;沉积环境;无冰区;南极

Abstract:

Relative frequency distributions of the various surface textures recorded on quartz grains can indicate the depositional environment. Surface textural analysis of quartz grains under some representative sedimentary environments on the Fildes Peninsula were performed by Scanning Electron Microcopy (SEM). The results suggest that glacial transportation had occurred on the most of quartz grains from various depositional environments in ice free area of King George Island and this correspond well to extensive glacial debris. Furthermore, there are some differently characteristic textures present on quartz grain from various depositional environments in studying area. For example, V shaped pits show high enough frequencies on modern beach sands, suggesting high energy subaqueous transport, and the striations were produced largely on the tills. Based on the data for surface texture occurring frequency, we classify samples into different groups in order to identify their depositional environment. The results show that ancient beach sands were preserved in the second, the third, the fifth marine terraces, and F 1 sample is predominantly composed of tills. These judgments are supported by filed survey. Therefore, surface textural analysis of quartz grains can be used as effectively auxiliary criterion for identification of depositional environment in Antarctic ice free area.