Uplift History of the Eastern Pamir Inferred from Inversion of Thermochronometric Data and River Profile

Abstract The Pamir salient accommodates a great amount of Cenozoic India-Eurasia convergence in the forms of thrusting, strike-slip faulting, extension, and gneiss dome formation. It thus becomes a key location for exploring the orogenic tectonic evolution. Here, we focus on the Eastern Pamir where extensional deformation dominates during the late Cenozoic. We conducted low-temperature thermochronological dating on bedrock samples collected from the footwall of the Kongur Shan normal fault together with inversion of the longitudinal river profile of the Gez River. Our new zircon and apatite (U-Th)/He (ZHe and AHe) data reveal young ages in proximity to the normal fault and older ages adjacent to the western Tarim Basin. By inverting the Gez River profile together with published and new thermochronological ages, we obtained a sustained uplift rate of ~3 mm/yr in the Kongur Shan dome since ~8 Ma, contrasting with no significant uplift to the east of the dome before the Pliocene. This uplift pattern can be interpreted as a result of the upward extrusion of crust materials along a flat–ramp–flat thrust fault at depth under the context of convergence.