A discussion on the deformation phases and tectonic process of the Southern Kunlun accretionary complex belt,in central Qinghai

The Southern Kunlun accretionary complex belt,which was formed in the process of the long-term northward subduction of the Tethys oceanic lithosphere plate during Caledonian-Indosinian period,played an important role in the eastern Kunlun orogenic belt.Based on the structural profile survey in Xueshuihe area,the authors investigated in detail contact relationship,material composition,and deformational-metamorphic characteristics of the outcrops in combination with the study of the microstructure under microscope and,as a result,recognized nine different tectonic massifs.On the basis of a comparative study of the structural deformation of each massif,the relative deformation sequence of the South Kunlun accretionary complex was tentatively established,and a 4-phase deformation was recognized.In combination with the regional tectonic evolution,the authors discussed the tectonic setting and the process of the deformation phases,and tried to establish an evolution model.It is held that the tectonic foliation experienced reformation and superimposition during the plateau uplift in east Kunlun accretionary complex.This study is significant for understanding the tectonic process of the Kunlun orogenic belt.