Arc magmatism is maintained through continuous recycling of fluid fluxes in subduction zones. A persistent enigma in magmatic arc evolution centers on the striking spatiotemporal variations in magma addition rates and compositional arrays documented in some arcs. Meanwhile, key subduction parameters governing thermal structure typically undergo gradual along-strike and temporal evolution. A widely held view posits an intrinsic linkage between these deep processes and shallow magmatic expressions. However, the intrinsic nature and details of this relationship remain poorly constrained. To address this challenge, we performed an integrated statistical synthesis and analysis of geochemical, geochronological, and geological datasets from Mesozoic arc plutonic rocks from the Lhasa terrane in southern Tibet. Our findings demonstrate three principal manifestations of intra-arc magmatic diversity:(1) episodic magmatic pulses, (2) systematic along-strike variations in magmatic tempo and composition, and (3) cross-arc migration of magmatic foci. Crucially, we establish genetic relationships between these variations through spatiotemporal-compositional correlations, revealing their ultimate control by episodic flattening and rollback of the Neo-Tethyan slab. The original east-to-west decreasing slab dip angle progressively modulated these dynamic processes. Our analytical approach on the Lhasa case provides a transferable framework for investigating whether slab dynamics fundamentally controls intra-arc magma diversities in other arc systems.
DownLoad: