太湖三山岛击变岩的发现及其意义  

THE DISCOVERY OF SHOCK METAMORPHIC ROCKS AT SANSHAN ISLAND OF TAIHU LAKE AND ITS SIGNIFICANCE

作　　者：傅成义 俞锦标[1] 王赐银[2] 严正富[2] 尹琳[2] 胡志宏[2] 李旭平[3] 傅国飞 

机构地区：[1]南京大学大地海洋科学系 [2]南京大学地球科学系 [3]南京化工学院硅工系

出　　处：《地理学报》1990年第2期253-256,T002,共5页Acta Geographica Sinica

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.

关 键 词：太湖 三山岛 击变岩 石英砂岩 

分 类 号：P588.212.3[天文地球—岩石学]