Crust-mantle transitional zone of Tianshan orogenic belt and Junggar Basin and its geodynamic implication

Abstract

The traveling time of the reflection waves of each shot point from the crust-mantle transitional zone has been obtained by data processing using wavelet transform to the waves reflected from the crust-mantle transitional zone. The crust-mantle transitional zone of the Xayar-Burjing geoscience transect can be divided into three sections: the northern margin of the Tarim Basin, the Tianshan orogenic belt and Junggar Basin. The crust-mantle transitional zone is composed mainly of first-order discontinuity in the Tarim Basin and the Junggar Basin, but in the Tianshan orogenic belt, it is composed of 7—8 thin layers which are 2—3 km in thickness and high and low alternatively in velocity, with a total thickness of about 20km. The discovery of the crust-mantle transitional zone of the Tianshan orogenic belt and Junggar Basin and their differences in tectonic features provide evidence for the creation of the geodynamic model “lithospheric subduction with intrusion layers in crust” for the Tianshan orogenic belt.