Provenance and Tectonic Setting of Clastic Deposits in the Devonian Xicheng Basin, Qinling Orogen, Central China

摘要

The Qinling orogenic belt is one of world's great collisional orogenic belts, which extends from the Pamirs–West Kunlun to the Korean peninsula and occupies a key position in understanding of the evolution and assembly of Asia. This belt separates the North China and South China blocks. Extensive, thick Devonian clastic rocks, sandwiched between the Shangdan and Mianlue suture zones, are mainly infills of the Xicheng Basin and provide the principal sedimentary record of tectonism in the Qinling orogen. Devonian infills were subdivided into three subunits: the Upper Devonian Dacaotan Group, the Middle–Upper Devonian Shujiaba Group, and the Lower–Upper Devonian Xihanshui Group. Their provenance and tectonic setting are critical to understanding not only the tectonic evolution of Asia but also the global aspects of collisional regions. Compared with Devonian strata in the eastern part of the Qinling orogen, the Xicheng Basin was not seriously modified by Mesozoic tectonism.