Late Cenozoic topographic growth of the South Tianshan Mountain Range: Insights from detrital apatite fission-track ages, northern Tarim Basin margin, NW China

Abstract

• Rocks with Mesozoic fission track ages were resided in the paleo-partial annealing zone for a long time. • The deformation commenced in the late Oligocene-early Miocene in South Tianshan. • The provenance of the Tarim Basin changed at 10 Ma due to rapid uplift of the South Tianshan Mountain Range. The Cenozoic deformation of the Tianshan Mountain Range within the framework of the India-Eurasia collision has been extensively studied. Previous thermochronologic studies of bedrocks in this range suggest a complex Triassic-Early Cretaceous tectonic evolution and subsequent tectonic quiescence in the Late Cretaceous-Palaeogene. Thus, constraining the exhumation and topographic growth of the Tianshan Mountain Range during the Cenozoic remains a challenge. In this study we report new detrital apatite fission-track ages for a Cenozoic sedimentary succession on the northern margin of the Tarim Basin (Kuqa River section). Thermochronologic age trends along the analyzed succession reveal two major age-shifts in sediments deposited at ∼ 23 Ma and ∼ 10 Ma, which we ascribe to major drainage reorganizations in response to uplift of the South Tianshan Mountain Range, an interpretation corroborated by published detrital zircon U-Pb and heavy mineral data. By comparing detrital apatite fission-track data with existing bedrock data, we infer that both North Tianshan, Yili-Central Tianshan and South Tianshan provided detritus to the Tarim Basin during the early and middle Miocene. At ∼ 10 Ma, the South Tianshan Mountain Range experienced rapid uplift and started forming a topographic barrier that blocked sediments flowing from North Tianshan and Yili-Central Tianshan into the Tarim Basin. We suggest that progressive topographic growth of the South Tianshan Mountain Range favored the aridification of the Tarim region by acting as a barrier to westerly winds.