摘要
太湖三山岛击变岩,宏观特征表现为崩解裂理;微观特征出现石英颗粒的晶体弯曲、多组微页理的面型特征、机械双晶、震变玻璃、焦石英及柯石英相变产生的放射状裂隙等,是陨石撞击地表的一种特殊地质现象。它的发现,是太湖成因研究中的重要进展。
In Sanshan islet of Taihu lake, several peculiar stones, identified to be well-developed shock metamorphic rocks, were first found by the authors. It is suggested that they were formed by the impact of an ancient giant meteorite on the Devonian quartzitic sandstones of the Wutong formation. Macroscopically, they do show some distinct disintegration partings. And microscopically, they are characterized by the development of bending of quartz grains, the presence of multiple sets of planur features, mechanical twining quartz crystals, the existence of diaplectic glasses, le-chatelerites and the radiating fractures in quartz grains which were thought to be caused by the
process of phase transformation from the precursor mineral──coesite to ordinary quartz. .AH
these phenomena might attribute to a peculiar geologic event caused by a sudden impact of a meteorite onto the ground surface. This discovery might cast a new light on the origin of Taihu lake, and it might be regarded as an important breakthrough in such a research field.
出处
《地理学报》
EI
CSSCI
CSCD
北大核心
1990年第2期253-256,T002,共5页
Acta Geographica Sinica
关键词
太湖
三山岛
击变岩
石英砂岩
Shock metamorphic rocks
Impact crater
Shanshan islet
Taihu lake
