A Reconstruction for the Late Paleozoic Tectonic Evolution of the Tekes Daban Area, Western Tianshan Mountains: Evidence from Unconformities

• Published in: Acta geologica Sinica (Beijing) 2011-10, Vol.85 (5), p.1127-1136
• Main Authors: LI, Yongjun, YANG, Gaoxue, WANG, Xiaogang, ZHANG, Tianji, LIU, Xiaoyu, YANG, Mingyi, TONG, Liming
• Format: Article
• Language: English
• Subjects: Basins; episode; Late Paleozoic; Sedimentation & deposition; unconformity; Western Tianshan Mountains
• ISSN: 1000-9515; 1755-6724
• DOI: 10.1111/j.1755-6724.2011.00545.x

: The identification of unconformities is the key to reconstructing tectonic evolution, revealing crust movement and establishing tectonic cycle. For a long time, there were some controversial issues on the episodes of Variscan cycle (especially on the period of Carboniferous‐Permian stages) of the Tianshan area. The essential questions fall on the numbers and property of unconformities in this area, for example, in the western Tianshan area. Previous research only recognized three or four fold movements. Detailed regional geological mapping of 1:50000 in the Tekes Daban area, western Tianshan have allowed us to characterize the seven unconformities within the Carboniferous‐Permian strata and understand its implications for tectonic reconstruction of the Tianshan orogen. Seven angular unconformities, which indicate that seven tectonic episodes occurred in the Late Paleozoic Period, were identified in this area. Therein, the newly discovered unconformities based on the angle‐unconformity between the Dongtujinhe and Keguqinshan Formations, and angle‐unconformity between the Wulansayi and Wulang Formations, respectively indicates the Tekes episode and Gongliu episode. The unconformity between the Dongtujinhe and Yishijilike Formations is angle‐unconformity instead of parallel unconformity indentified by previous research, so the former Bogda ascending can be revised as Bogda movement. Therefore, these newly identified seven episodes, including the Tekes episode, suggest that there are seven tectonic movements in the Tianshan area at least. This has significant implications for reconstruction of the Late Paleozoic tectonics in the Tianshan Area, NW China.