新甘交界红柳河地区辉长质糜棱岩的确定及其意义

The Discovery of Gabbric Mylonites from Hongliuhe Ophiolitic Complex,NW China

新甘交界处的红柳河蛇绿岩套中发育辉长质糜梭岩,辉石、斜长石具有良好的塑性变形特征。辉长质糜棱岩主要集中于蛇绿岩套的堆品辉长岩单元内,可能是洋壳生成后不久下部不同层次间滑脱的产物。

The preliminary data ar,e presented on microstructures of the gabbricmylonites from the Hongliuhe(HLH)(红柳河)ophiolitic complex,in the borderarea between Xinjiang and Gansu,NW China.The HLH ophiolitic complex areremnants of the Silurian South Tianshan oceanic crust,while the Mid-TianshanTerrane collided with the Tarim plate in the Upper Carboniferous.The accumula-tive gabbros from the HLH ophiolites preserve a fine example of mylonitic rocks.The ductile deformation of clinopyroxene and plagioclase in HLH area are differentfrom those in granulite terrain of North China craton.Generation of these gabbricmylonites is interpreted instead as due to ductile shear at the lower oceanic crustnear the spreading centre,soon after new oceanic crust was formed.