秦岭造山带佛坪基底杂岩的地质特征

Geological features of the Foping basal complex, Qinling orogenic belt

综合研究表明 ,佛坪基底杂岩是由普遍遭受多期强烈变形变质作用和混合岩化作用的变质火山 -沉积岩系和中酸性侵入岩构成的结晶杂岩系 ;结晶杂岩的形成年龄为2 2～ 18亿年 ,受强烈构造热事件改造的年龄为 2亿年左右 ;佛坪基底杂岩经历了基底杂岩形成时期、主造山期和主造山期后 3个不同演化时期的构造变形的叠加、改造 ,主造山期最主要的变形是在早期盖层沿其与基底的界面发生逆冲推覆构造的基础上发生热穹隆叠加变形。

Systematic research shows that the primitive rock of the Foping basal complex consisted of volcanic sedimentary rocks and mid acid intrusive rocks, which suffered widespreadly multiple phase of intense deformation, metamorphism and migmatization The forming age of the complex is 2 2～1 8Ga, and the reforming age is about 200Ma The complex was subjected to three different evolution periods of tectonic deformation, that is, the period of complex formation, principal orogenesis and post orogenesis During the period of principal orogenesis, the main deformation of the complex characterized by the superimposed deformation of the thermal doming on the basis of the thrustting nappe structure