西昆仑麻扎构造混杂带变形特征

The Deformation Characteristics of Mazha Tectonic Melange in West Kunlun

麻扎构造混杂带南北边界断裂具有明显的韧性变形特征,笔者通过野外区域地质调查重新对混杂带边界断裂建立了新的认识,认定南北边界断裂具有早期韧性剪切与晚期脆性活动的多期次构造活动特征。早起韧性剪切发育了大量糜棱岩化与不对称旋转碎斑现象。通过对北边界断裂火山弧岩块的岩石化学分析,得出了麻扎构造混杂岩带内大量出露的岩浆岩形成于板块边缘的岛弧构造环境的结论。

South and north boundary faults of the Mazha tectonic melange belt have obvious deformation and toughness. Through field regional geological survey, the author aimed to establish a new understanding of the mixed boundary fault zone, and found that the north and south boundary faults have multiple periods of tectonic features of early ductile shear and late brittle ac- tivities. The early ductile shear developed a lot of mylonitization and asymmetry rotated porphyroclast phenomenon. Through the petrochemical analysis on north boundary fault arc volcano rock, it is concluded that the widespread magmatite in Mazha tectonic melange belt formed in the island arc tectonic environment on the edge of the plate.