Publication Date:
2020-09-29
Description:
The Yadong-Gulu graben preserves the kinematic and temporal relationships between east-west directed extension in southern Tibet and north-south extensional strain in the Himalaya. In the Yadong region, distinct outer and inner top-down-to-the-north segments of the South Tibetan detachment system (STDS) are recognized. Herein, we combine high/medium-T (U–Pb, 40Ar/39Ar) and low-T (AFT, ZHe and AHe) thermochronometry to investigate the timing of slip across the STDS and Yadong-Gulu structures. These data demonstrate that the cessation of the Yadong shear zone, the structurally outer, ductile segment of the STDS, occurred ca. 20 Ma and that motion along the inner brittle-ductile Zherger La detachment continued after ca. 16.6 Ma, ending by 11 Ma. The cooling history in the immediate STDS footwall is characterised by two main episodes of relatively rapid cooling and exhumation. The first occurred in middle Miocene (ca. 15-11 Ma), and is common along strike of the innermost STDS footwall, related to cooling of the STDS. The second occurred in late Miocene-Pliocene (ca. 7-3 Ma), and is local to the Yadong-Gulu graben footwall in NW Bhutan, indicating that late Miocene-Pliocene slip along the graben system contributed to exhumation of the STDS east of the graben rift.Supplementary material:https://doi.org/10.6084/m9.figshare.c.5132941
Print ISSN:
0016-7649
Topics:
Geosciences
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