Spatial and temporal reconstruction of postcollisional potassic rocks: Implications for mantle flow beneath the SE Tibetan Plateau

Abstract Postcollisional potassic magmatism occurs throughout the Alpine-Himalayan belt, providing a crucial record of crust-mantle interaction and associated ore-forming processes in a collisional orogen. Unravelling its spatial and temporal record is often complicated by intense tectonic deformation, including strike-slip faulting. New Hf-Nd isotope mapping of two Cenozoic potassic rock assemblages along the Ailaoshan–Red River shear zone from the SE Tibetan Plateau, together with Sr-Nd-Hf isotope evidence, establishes that these two segments of potassic magmatism were originally juxtaposed prior to strike-slip faulting. By reconstructing the spatiotemporal distribution of the potassic rocks, we identified a zone of mantle upwelling and lateral flow in response to India-Asia collision. This activity matches the distribution of porphyry Cu-Au and carbonatite-associated rare earth element deposits in the area, demonstrating the significant contribution of mantle materials to the metallogenic processes in collisional settings.