Kinematics of Cenozoic Shortening of the Hotan Anticline Along the Northwestern Margin of the Tibetan Plateau (Western Kunlun, China)

Abstract

Kinematic constraints on the Cenozoic deformation along the northwestern edge of the Tibetan Plateau remain limited. Combining surface geological data and seismic profiles, we document the structural geometry and kinematics of the large‐scale east‐west striking Hotan anticline, along the foothills of the Western Kunlun Range. Four new balanced cross sections are constructed, and the temporal evolution of deformation is deciphered from the exceptionally well‐imaged growth strata at the front of the fold. This anticline results from a broad fault‐bend fold, subsequently deformed by a footwall duplex. The total shortening across the whole structure is relatively constant along strike, from ∼40 to ∼35 km. However, the shortening accommodated by the duplex varies laterally from ∼50–40% to 0% of the total shortening. Two distinct successive patterns of growth strata are recognized and are interpreted to be representative of deformation on the ramp anticline, followed by deformation on the duplex. The onset of deformation initiated by ∼16 Ma. Deformation of the underlying duplex began at ∼12 Ma to the west and subsequently propagated eastward. From these results, we determine a shortening rate of ∼5 mm/yr from ∼16 to ∼8–9 Ma across the Hotan thrust system, followed by a significant decrease in shortening rate, possibly down to <0.5 mm/yr. We explore the significance of this deceleration of deformation at the scale of the Western Kunlun foothills and at a broader regional scale as it may point to a regional kinematic reorganization by the late Miocene.

Surface Processes Driving Intracontinental Basin Subsidence in the Context of India–Eurasia Collision: Evidence from Flexural Subsidence Modeling of the Cenozoic Southern Tarim Basin along the West Kunlun Foreland, NW Tibetan Plateau

“…The southern Tarim Basin, located along the northwest margin of the Tibetan Plateau (Fig. 1a, b), provides an excellent example to address this issue, as it shows (1) a typical foreland basin geometry (e.g., Laborde et al, 2019;Li C et al, 2020;Chen et al, 2021;Li C Y et al, 2021;Wang S L et al, 2021), (2) a high orogenic load consisting of the West Kunlun orogen (e.g., Cheng et al, 2017;Laborde et al, 2019;Baby et al, 2022) and (3) thick Cenozoic deposits with the thickness of the Cenozoic strata reaching >10 km at the Yecheng depocenter (Fig. 1b; e.g., Zheng et al, 2015;.…”