太古宙高级变质杂岩的近水平顺层剪切构造变形及岩石深熔作用——以内蒙古大青山地区为例

Sub-horizontal Shearing Structures and Anatexis of Archean Lower Crustal Rocks in Daqingshan Area,Inner Mongolia

内蒙古大青山地区是华北地台北缘以富含麻粒岩系和孔兹岩系为特征的高级变质地层发育的地区之一 ,其中太古宙的岩石普遍经历了麻粒岩相变质与变形作用。在高级变质杂岩中变形构造复杂 ,其中近南北向和近东西向构造构成了本区的基本构造格局。研究发现 ,在高级变质地层中还存在着一期近水平顺层剪切构造变形形迹 ,其形成于下地壳麻粒岩相。近水平顺层剪切构造变形不仅导致麻粒岩系与孔兹岩系以近水平构造面相接触 。

Daqingshan area of Inner Mongolia is one of the high-grade metamorphic terrains rich in khondalite and granulite series in the northern margin of North China platform. Archean rocks in the area are generally deformed and metamorphosed at guanulite facies. The high-grade complexes have quite complicated structural styles,with the dominant structural framework formed by N-S trending and E-W trending structures. In the high grade terrain there is a group of sub-horizontal shearing structural features developed in lower crust granulite facies environment. The sub-horizontal structural deformation not only results in horizontal contact of khondalite with ulite series,but also induces the partial melting of the khondalite and granulite series.