1. Paleocene Neo-Tethyan slab rollback constrained by A1-type granitic intrusion in the Gaoligong–Tengliang–Yingjiang belt of the Eastern Himalayan Syntaxis, SE Tibet.
- Author
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Liu, Zheng, Liao, Shi-Yong, Tan, Shu-Cheng, He, Xiao-Hu, Wang, Guo-Chang, Wang, Dong-Bing, and Zhou, Qing
- Subjects
SLABS (Structural geology) ,MAGMAS ,ZIRCON ,SUBDUCTION zones ,SUBDUCTION ,AMALGAMATION - Abstract
Slab rollback is one of the primary processes in shaping tectonic framework. However, in the Tibet–Himalaya orogen, the timing of the Neo-Tethyan slab rollback remains controversial. In this contribution, we investigated an early Paleocene (ca. 62 Ma) A
1 -type granitic intrusion (South Gongshan) from the Gaoligong–Tengliang–Yingjiang (GTY) area, SE Tibet. It is mainly characterized by high 10,000*Ga/Al ratios (4.0–9.1) and extremely high HFSEs contents (Zr + Nb + Ce + Y = 669–3146 ppm), with relatively low Y/Nb ratios (0.8–1.1). The samples collected from the intrusion exhibit high zircon εHf (t) (+1.1 to +5.7) and whole-rock εNd (t) values (− 0.8 to − 3.1). Geochemical data indicated that it was probably produced by extreme FC of asthenospheric mantle-derived basaltic magmas. Together with results from convergence rate between India and Asia, the emplacement of the South Gongshan intrusion was likely to be associated with a transition from flat to steep subduction triggered by the Neo-Tethyan slab rollback. We proposed that the Neo-Tethyan slab rollback beneath the GTY area might have occurred at ca. 62 Ma. [ABSTRACT FROM AUTHOR]- Published
- 2019
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