摘要
含柯石英、金刚石榴辉岩是南大别超高压变质岩石的主体，在这些榴辉岩的未退变质核心、退变质斜长角闪岩及超高压围岩中，保存有大量不同变质时期的宏观—微观变形构造．其中主要的变形构造是在单剪应力状态下，由具有顶端指向ＮＷ动向的角闪岩相变形作用Ｄ２形成的ａ型褶皱Ｆ２，以共轴样式叠加于纯剪应力状态下榴辉岩相变形作用Ｄ１形成的斜卧褶皱Ｆ１之上的二次叠加褶皱，总体形态符合Ｒａｍｓａｙ第三种干涉型．这两期变形作用揭示了超高压变质岩石在折返过程中存在两种动力学机制，它们相续作用才使得这些超高压岩石出露地表．
Coesite-diamond bearing eclogites are main body of ultrahighpressure metamorphic rocks at Southern Dabie Mountains.There are many macro-microscopic deformational structures in eclogites' country rocks which experienced ultrahighpressure metamorphism,amphibolites retrograded from eclogites,and unretrograded eclogites.These structures were developed during metamorphism processing.The principal deformational structure is the atype fold F2 with top-to-NW moving senses developed under amphibolitic facies deformational event D2 by simple shear strain state,which superimpose on the inclinded recumbent fold F1 developed under eclogitic facies deformational event D1 by pure shear strain state.Its structural geometry accords with type Ⅲ interference pattern of surperimposed folds by Ramsay.Two deformational stages reveal there are two kinds of geodynamic mechanisms acting during exhumation of these ultrahighpressure rocks.The mechanisms act in succession and dominate the exhumation process in uplifting of ultrahighpressure metamorphic rocks.
出处
《南京大学学报（自然科学版）》
CAS
CSCD
1998年第3期330-340,共11页
Journal of Nanjing University（Natural Science）
基金
国家自然科学重大基金
国家教委博士点基金
关键词
超高压变质岩石
变形构造
叠加褶皱干涉型
Dabie Mountains,ultrahighpressure metamorphic rocks,deformational structure,interference pattern of surperimposed folds,mechanism of exhumation
