西昆仑康西瓦南一带康西瓦岩群的厘定及其地质意义

Redefinition of the Kangxiwa Group in South Kangxiwa Area of West Kunlun and Its Geological Significance

康西瓦岩群是"康西瓦"等四幅1:25万区域地质调查工作,从前人所划的三叠系克勒青河群中新解体的中-深变质的构造岩石地层单位。该套地层主要为一套中-深变质碎屑岩夹少量大理岩,分布于康西瓦晚期脆性断层南一带,与黄羊岭群及三叠系巴颜喀拉山群为断层接触,被寒武纪及侏罗纪花岗岩侵入。笔者对其从岩石特征、变质变形特征、微量元素和稀土元素特征等方面进行了详细研究,并将其与铁克里克地层区的古元古界埃连卡特岩群进行对比,结果发现二者基本相同,应归为同一构造岩石地层单位。说明西昆仑与塔里木陆块可能具有统一的基底演化特征,后期从塔里木陆块上裂解开来。该套地层的厘定为西昆仑的物质组成与演化研究提供可靠的资料。

Kangxiwa group based on mesometamorphical lithostratigraphic unit of Triassic Shaks- gain River groups is newly separated from the job of four Kangxiwa 1 ： 250000 regional geological survey works. Distributed in the southern area of the late Kangxiwa brittle faults, the strata are mainly composed of medium- deep mesometamorphical clastic rocks and little marble, and intru- ded by the Cambrian and Jurassic granite. Characteristics of petrology, metamorphism, deformation, trace element and rare earth element of the group were studied and compared in details with Ailiankate group. Results show that the two groups are basically identical and should be classified as the same tectonic rock strata unit. It is further demonstrated that the west Kunlun Mountain has the same basement evolution characteristics with the Tarim block. The redefinition of strata provides reliable information for material composition and evolution studies of west Kunlun.