关键词: 地学断面, 深浅构造, 拆沉作用, 天山

Abstract: The Tianshan Mountains originated from continent-continent collision during late Paleozoic era,and has experienced typical intra-continental orogenic process during Mesozoic-Cenozoic era. The architecture and activity of the shallow and deep structures of the Tianshan Mountains have attracted the attention of many geoscientists. Based on several geophysical prospecting data and comprehensive geological tectonic study,the shallow and deep structures of the middle segment of the Tianshan Mountains have been mapped in the light of the Tianshan Geoscience Transect. The result shows that the main geological units associated with the complexity of deep structures are displayed symmetrically from old to young on both sides of the suture zone of continental collision in Paleozoic era. This may reflect the collision process and the tectonic evolution in the later geological period. It is discovered that a low-velocity and high-conductivity layer of about 200km in width and about 10km in thickness exists on top of the upper mantle beneath the middle segment of the Tianshan Mountains. It is considered to be the residual lower crust resulted from the delamination between the crust and mantle due to the rejuvenated orogenic process of the Tianshan Mountains during Mesozoic-Cenozoic era.

Key words: Geoscience Transect, shallow and deep structures, delamination, Tianshan