New discovery and geological significance of Late Silurian–Carboniferous extensional structures in Tarim Basin

• Published in: Journal of Asian earth sciences 2015-02, Vol.98, p.304-319
• Main Authors: Li, Yue-Jun, Wen, Lei, Yang, Hai-Jun, Zhang, Guang-Ya, Shi, Jun, Peng, Geng-Xin, Hu, Jian-Feng, Luo, Jun-Cheng, Huang, Zhi-Bin, Chen, Yan-Gui, Zhang, Qiang
• Format: Article
• Language: English
• Subjects: Back-arc rifting; Late Silurian–Carboniferous normal fault; Post-orogeny stress relaxation; Seismic interpretation; Tarim Basin
• ISSN: 1367-9120; 1878-5786
• DOI: 10.1016/j.jseaes.2014.11.020

•First discovery of S3–C extensional structures in Tarim.•S3–C extensional structures in S Tarim represent post-orogenic stage of Kunlun.•S3–D extensional structures in N Tarim Basin was related to S Tianshan rifting. Late Silurian–Carboniferous extensional structures have been discovered after careful interpretation of seismic reflection data in western Manjiaer Sag, Central Tarim Basin in central Asia. The extensional structures comprise numerous small normal faults in nearly N–S strike direction. Groups of normal faults in profile show features suggestive of negative flower structures and small horst-graben structures. Based on growth index calculation, these extensional structures formed in the Late Silurian period, continued activity in the Devonian and Carboniferous and then ceased at the end of Carboniferous. The peak-stage of normal fault activity occurred in Late Silurian. Late Silurian–Carboniferous normal faults also developed in the Tazhong and Tabei areas, which implies that Tarim Basin were under regional extensional tectonic setting during that periods. The extensional structure in southern Tarim resulted from the post-orogeny stress relaxation of the Kunlun Early Paleozoic orogenic belt, and those in northern Tarim resulted from the Paleozoic back-arc rifting which led to the opening of South Tianshan ocean.