黄河公伯峡古风化花岗岩石英表面结构的工程地质研究

本文对黄河公伯峡电站古风化花岗岩中的石英表面结构进行了扫描电镜观察。其特征表明是在典型的高能化学环境下形成的,这与现代风化花岗岩石英表表面结构特征明显不同,为鉴定古风化花岗岩提供了依据。

ENGINEERING GEOLOGICAL STUDY ON QUARTZ GRAINSURFACE TEXTURE OF PALAEO-WEATHERED GRANITEIN GONGBO GORGE OF THE YELLOW RIVER

In this paper the characteristics of quartz grain surface textures of palaeo-weathered granite in the damsite of Gongbo Gorge Hydropower Station (under design) have been given. Scanning electron microscopic observations and photographs manifest that these characteristics are different from that of the present weathered granite. Quartz grains in palaeo-weathered granite are mostly rounded because of strong dissolution, fracture surfaces were often dissolved so as they seem to be not so clear, developing with many pores, holes and cavities, and silicate deposits on the surface of quartz grain are commonly ob-served, and these coexist both deposition and dissolution. All of these characteristics show clearly that the quartz grain surface textures in palaeo-weathered granite were formed under the chemical circumstances of high energy. Present weathered granite has never undergone such a circumstance, so its quartz grain surface textures are quite different from thatof palaeo-weathered granite. By means of these difference,the palae-weathered granite can be distinguished from present weathered granite.