SOUTH TIANSHAN: A LATE PALEOZOIC OR A TRIASSIC OROGEN?

Abstract

The South Tianshan Orogen between the Yili-Kazakhstan and Tarim-Karakum plates is one of the representatives of the Central-Asia. type' Orogen and has undergone complicate tectonic evolution and crustal growth processes. It has been traditionally regarded as a Hercynian foldbelt or a Late Paleozoic collisional orogenic belt. However, some researchers have proposed that it may be a Triassic collisional orogenic belt recently. Here, we have summarized the age dating data of ophiolites, high-pressure metamorphic rocks and granites and discussed its collisional time. The collisional orogenesis in the western segment of Chinese South Tianshan Orogen may start in early Carboniferous (345Ma) and end at the end of late Carboniferous (ca. 300Ma). The South Tianshan and the whole Central Asia may have evolved into a post-collisional stage in Permian. The data obtained up to now have demonstrated that the South Tianshan Orogen is a late Paleozoic collisional orogenic belt, not a Triassic one.