Petrogenesis of Late Miocene High Ba–Sr Granitoids in Eastern Pamir, Northwest Tibetan Plateau: Insights into Lithospheric Mantle Evolution and Geodynamic Processes during India–Asia Bidirectional Subduction.

This article focuses on the petrogenesis and geodynamic implications of Late Miocene (ca. 11 Ma) high Ba–Sr granitoids from the Kuzigan, Karibasheng, and Zankan plutons in the eastern Central Pamir, northwest Tibetan Plateau. Geochemical, isotopic, and geochronological data indicate that the high Ba–Sr syenites originated from enriched sub-continental lithospheric mantle metasomatized by subduction-related sediments derived primarily from the Indian plate (~20–30%) and to a lesser extent the Asian plate (~1–3%), while the associated syenogranites formed through fractional crystallization of these syenitic magmas. The Karibasheng monzogranites, in contrast, were generated by muscovite-dehydration melting of ancient metasedimentary rocks in the thickened lower crust. The study proposes a west-to-east magmatic migration linked to episodic delamination of the Pamir lithosphere, which induced asthenospheric upwelling, mantle melting, and subsequent crustal melting, processes that contributed to Miocene magmatism and episodic plateau uplift in the region. These findings highlight the complex interactions between continental collision, lithospheric delamination, mantle metasomatism, and crustal growth during the Cenozoic evolution of the Pamir Plateau.