我国热带亚热带部分地区花岗岩和片麻岩中黑云母风化研究

综合应用Ｘ射线衍射、扫描电镜、透射电镜及偏光显微镜等技术手段研究了我国热带、亚热带部分地区花岗岩和片麻岩中黑云母的风化现象。结果表明，化学风化产物主要有黑云母／蛭石不规则间层矿物、水黑云母、蛭石、０．７ｎｍ埃洛石及铁的氢氧化物（氧化物）等。影响黑云母风化及次生产物形成的主要因素包括黑云母的晶体结构和化学成分、气候、风化壳母岩的矿物成分等。

WEATHERING OF BIOTTTE IN SOME WEATHERED GRANITE AND GNEISS FROM SOME SUBTROPICAL AND TROPICAL AREA OF CHINA

Weathering of biotite and the secondary Prchcts in some weathered granite and gneiss from some subtropical and tropical areas are studied by means of X-ray diffraction, electron mi croscopy and light microscopy. Biotite in these areas has suffered salient chemical weathering. The major secondary products derived from the weathering of biotite mainly are venmiculite, hydribiotite,irregularly interstratified-layer biotite-vermiculite, 0. 7 nm halloysite, and ferric hydroxide or oxide,etc. etc. Weathering of biotite to forming 0. 7 nm halloysite is probably a gndual transfomtion with defferent stages such as: irregularly interstratified mineral, hydrobiotite, vermiculite etc. which can't be well-defined by light microscope because of the similarities in optical characteristics of the intermediate minerals. Factors affecting the weathering of biotite and formtion of the secondary products include the cryst-allographic narures and chemical components of biotite,temperature and plenty of precipitation,and mineralogical composition of the granite and gneiss.