The Mesozoic Closure of the Paleo-Tethys Ocean: Constraints from Zircon U–Pb Ages, Hf and Nd Isotopes of The Granitic Plutons in the Hoh-Xil-Songpan-Ganzi

Research on the Hoh-Xil-Songpan-Ganzi (HXSG) complex reveals critical insights into the Mesozoic closure of the Paleo-Tethys Ocean, a pivotal event shaping the eastern Tibet Plateau. The study identifies two distinct tectonic-magmatic phases: syn-collision magmatism (243–227 Ma) and post-collision magmatism (219–185 Ma), linked to the convergence of the North China, Yangtze, and Qiangtang blocks. Using zircon U-Pb dating, Hf-Nd isotopic analysis, and geological data, the research demonstrates that the subduction of oceanic lithosphere led to lithospheric thickening and delamination, followed by asthenospheric upwelling and crustal melting. This transition from compression to extension is evidenced by diverse granitic plutons, including high Ba-Sr granite and adakite granitoids, sourced from varying depths—from the mantle to the upper-middle crust. The findings provide a robust framework for understanding the tectonic evolution of the HXSG complex during the Early Mesozoic.

Dong, J., Zou, H., Liu, H., Li, Y., & Jiang, X. (2019). The Mesozoic Closure of the Paleo-Tethys Ocean: Constraints from Zircon U–Pb Ages, Hf and Nd Isotopes of The Granitic Plutons in the Hoh-Xil-Songpan-Ganzi. Journal of Coastal Research, 94(sp1), 101. https://doi.org/10.2112/si94-019.1