Millennial slip rates of the Tazang fault, the eastern termination of Kunlun fault: Implications for strain partitioning in eastern Tibet
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- 作者：Junjie Ren ; Xiwei Xu ; Robert S. Yeats ; Shimin Zhang
- 关键词：Tazang fault ; Kunlun fault ; Slip rate ; Eastern Tibet ; Displaced terrace riser ; Min Shan platform
- 刊名：Tectonophysics
- 出版年：26 November, 2013
- 年：2013
- 卷：608
- 期：Complete
- 页码：1180-1200
- 全文大小：8573 K
文摘
The way of slip transformation and strain partitioning at the eastern termination of the Kunlun fault system remains unclear, and the question of whether this fault system is an important part for lateral extrusion of Tibetan crust is debatable. The Tazang fault is regarded as the easternmost continuation of the Kunlun fault system, and its late Quaternary activity is unknown. In this paper, we use displaced geomorphic features combined with radiocarbon and optically stimulated luminescence (OSL) dating to determine millennial slip rates along the Tazang fault. Our data yield a 1.4-3.2 mm/yr left-slip rate on the western Tazang fault, similar to that on the Maqu segment of the Kunlun fault. Tectonic geomorphology proposes that displacement on the Kunlun fault is probably transferred to the Tazang fault via a pull-apart basin. The eastern Tazang fault has a dominant reverse motion that decreases eastward from ~ 1.5 mm/yr to 0.2-0.3 mm/yr at the easternmost part. Displaced terraces indicate that the eastern strand of the northern Longriba fault is active in the Holocene and has a ~ 0.8 mm/yr right-lateral slip rate with a ~ 0.3 mm/yr reverse component. Millennial slip rates and geodetic results show that the decrease of left-lateral motion along the Tazang fault is mainly transformed into crustal shortening along the nearly N-S-trending Longriba, Minjiang, and Huya faults, probably resulting in uplift of the Min Shan. Our results also indicate that the deformation along the Tazang fault is not transferred to beyond the border of the plateau, and the Kunlun fault is not an important tectonics for Tibetan extrusion.