Cenozoic uplift, exhumation and deformation in the north Kuqa Depression, China as constrained by (U–Th)/He thermochronometry

Abstract

Placing spatial and temporal constraints on deformation, uplift and exhumation using thermochronology methods can shed light on Cenozoic orogenic evolution in the Kuqa foreland. New apatite (U–Th)/He and previously published apatite fission track thermochronology are combined with vitrinite reflectance data and modeling to compile a low temperature, multi-stage thermal history of tectonic uplift/thrust and exhumation. A rapid uplift and exhumation event originated in South Tianshan during the Eocene (~46Ma), with systematic younging of mean apatite (U–Th)/He ages from north to south (from the margin towards the interior). Uplift and exhumation south edge of the Biyoulebaoguzi anticline in the northern monocline belt at ~36Ma with more than 3400m of stratum denuded. Subsequently, deformation and uplift south edge of the Biyoulebaoguzi anticline in the northern monocline belt at ~36Ma with more than 3400m of stratum denuded. Subsequently, deformation and uplift extended to the northern edge of Kelasu–Yiqikelike at ~10Ma and then at ~6Ma, the Kanyaken anticline formed and uplifted resulting in 3000–3700m of overburden erosion. The data support sequential southward propagating deformation and uplift (inferred exhumation) in the north Kuqa Depression during the Cenozoic, probably as a result of the collision of India with Asia far to the south of the Tianshan.