Late Quaternary slip rates of the thrust faults in western Hexi Corridor (Northern Qilian Shan, China) and their implications for northeastward growth of the Tibetan Plateau
Late Quaternary slip rates of the thrust faults in western Hexi Corridor (Northern Qilian Shan, China) and their implications for northeastward growth of the Tibetan Plateau
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DOI：
10.1130/ges00775.1
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发表时间：
2013-04
期刊：
影响因子：
2.5
通讯作者：
Zheng Wen-jun;Zhang Huiping;Zhang Peizhen;P. Molnar;L. Xingwang;Yu Daoyang
中科院分区：
文献类型：
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作者：
Zheng Wen-jun;Zhang Huiping;Zhang Peizhen;P. Molnar;L. Xingwang;Yu Daoyang
我们确定了嘉峪关断层的滑动速率为0.22 +/- 0.03 mm a（-1）和0.11 +/- 0的垂直分量。我们使用了结构调查、航空照片图像分析、地形剖面、光学激发发光（OSL）测年和Be-10曝光测年。为了量化断层的滑动速率，我们对保存完好的断层陡坡进行了识别和调查，并在扇形表面和类似2米深的坑内取样了富含石英的鹅卵石和鹅卵石，以确定地表暴露年龄和沉积前继承。我们的滑移率属于过去，类似于115 ka。据此推断，从东经95°E至阿尔金断裂带东端的滑动速率减小与这些逆冲断裂带的低滑动速率有关。玉门盆地平行阿尔金断裂带方向的总缩短幅度为0.90 ~ 1.43 mm a(-1)，说明该断裂带东端的左旋走滑确实被玉门盆地内的变形所吸收。
We determined vertical components of slip rates of 0.22 +/- 0.03 mm a(-1) for the Jiayuguan fault and 0.11 +/- 0.03 mm a(-1) for the Jintanan Shan fault, which lie along the northeastern edge of the Tibetan Plateau and in the western Hexi Corridor (Northern Qilian Shan, China). We used structural investigations, air-photo imagery analysis, topographic profiling, optically stimulated luminescence (OSL) dating, and Be-10 exposure dating. To quantify the slip rates along the faults, we identified and surveyed the well-preserved fault scarps, and we sampled quartz-rich pebbles and cobbles on fan surfaces and within similar to 2-m-deep pits to determine surface exposure ages and pre-depositional inheritance. Our slip rates pertain to the past similar to 115 ka. They are consistent with previous geological and GPS constraints that suggest that NNE-SSW shortening across the northeastern Tibetan Plateau has been distributed onto several active faults and that shortening is partitioned into low slip rates of <= 1 mm a(-1) on each fault. We infer that the decreasing slip rate from 95 degrees E eastward to the eastern end of the Altyn Tagh fault and the low slip rates of these thrust faults are related. The total shortening in the direction parallel to the Altyn Tagh fault in the Yumen Basin of 0.90-1.43 mm a(-1) attests that left-lateral strike slip at the eastern end of the fault has indeed been absorbed by deformation within the Yumen Basin. We infer that the Tibetan Plateau continues to grow northeastward by thrust faulting at low rates and by folding on the northeastern edge of the Hexi Corridor basin.