摘要
本文从岩石及矿物的变质—变形关系和化学成分研究证明,龙江岩系①中蓝片岩与绿片岩的共存不是单一变质事件的产物,而是构造变动和不连续变质作用叠加的结果。早期蓝片岩形成在一种高压低温,高氧逸度环境。后经构造变动,转变为地热梯度较高的变形环境中,遭受韧性变形和以增温为主的绿片岩相变质作用的叠加。其间,钠质闪石向钠钙质闪石的转变,代表一种不连续的增温事件,而钠钙质闪石向钙质闪石的转变反映一种连续的增温过程。
The metamorphism-deformation relationships of rocks and minerals and their chemical characteristics indicate that coexistence of blueschist and greenschist in the Longjiang Suites do not result from single metamorphic event, but from the tectonism and discontinuous metamorphism. event,but from the overprint of tectonism and discontinuous metamorphism.By late influence of tectonic movement, early formed blueschists under high-pressure and high-oxygen fugacity were transformed into high geoth-ermal gradient deformation belt, and suffered ductile deformation and greenschist facies metamorphism. In the process of the deformation metamorphism,transition of sodic amphibole to sodic-calc amphibole represents a dis-continuously increasing temperature, and that of sodic-calc amphibole to calc amphibole reveals a continuously increasing temperature.
关键词
蓝片岩
绿片岩
岩系
构造演化
blueschist, greenschist,composite terrain,discontinuous meta- morphism
