First tectonic-geomorphology study along the Longmu–Gozha Co fault system, Western Tibet
First tectonic-geomorphology study along the Longmu–Gozha Co fault system, Western Tibet
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DOI：
10.1016/j.gr.2015.03.008
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发表时间：
2017
影响因子：
6.1
通讯作者：
M. Chevalier;J. Pan;Haibing Li;Zhiming Sun;Dongliang Liu;J. Pei;Wei Xu;Changde Wu
中科院分区：
文献类型：
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作者：
M. Chevalier;J. Pan;Haibing Li;Zhiming Sun;Dongliang Liu;J. Pei;Wei Xu;Changde Wu
隆木-戈扎错左行走滑断裂系位于西藏西部偏远地区，与阿尔金断裂（ATF）和喀喇昆仑断裂（KF）构成三重连接。阿什库勒断裂、戈扎错断裂和龙木错断裂为明显的左行雁列式断裂，共同构成LGCF系统。虽然缺乏记录，量化其活动仍然是一个关键问题，以了解运动学和青藏高原西部的构造历史。事实上，喀拉喀什断层（ATF的NW段）、LGCF和KF共同控制着西藏西部的构造，而西藏西部的构造本身又控制着西藏向东的挤压，LGCF充当了由于印度向北的撞击而导致的青藏高原向东运动的自然边界。LGCF系统显示出清晰和令人印象深刻的形态学迹象的左侧活动剪切，我们量化使用现场测量（地面激光雷达）沿着与10 Be表面曝光测年。我们的数据表明，滑动率< 3毫米/年，与大地测量和块体模型研究一致。虽然它与卡拉喀什断层的滑动速率相当（~ 2 mm/年），但它小于沿着ATF和KF的滑动速率（分别> 9和> 8 mm/年），因此，位于ATF和卡拉喀什断层之间的阿什库勒地堑及其周围地区很可能存在几mm/年的伸展。附近有许多近期构造相关事件的证据，如1951年的火山喷发以及2008年和2014年的玉田7.3级地震，证明了其高活动性。此外，LGCF的雁列几何形状和与ATF相同的方向，以及与周围断层相比较小的地质偏移和较低的滑动速率，表明ATF的这一段可能是最近的。
The Longmu–Gozha Co left-lateral strike-slip fault system (LGCF) is located in remote western Tibet, forming a triple junction with both the Altyn Tagh fault (ATF) and the Karakorum fault (KF), the two major strike-slip faults in the region. The Ashikule, Gozha Co and Longmu Co faults are clear and distinct left-stepping en-echelon faults, together forming the LGCF system. Although poorly documented, quantifying its activity remains a key problem to understand the kinematics and the tectonic history of the westernmost Tibetan Plateau. Indeed, the Karakax fault (NW segment of the ATF), LGCF and KF together control the tectonics of western Tibet which itself controls the extrusion of Tibet towards the east, with the LGCF acting as a natural boundary for eastward motion of the Tibetan Plateau due to India's northward impingement. The LGCF system shows clear and impressive morphological indications of left-lateral active shear, that we quantify using field measurements (terrestrial LIDAR) along with10Be surface-exposure dating. Our data suggest a slip-rate < 3 mm/yr, consistent with geodetic and block model studies. While it is on the order of the Karakax fault slip-rate (~ 2 mm/yr), it is smaller than those along the ATF and KF (> 9 and > 8 mm/yr, respectively), yielding a few mm/yr of extension accommodated most likely in the Ashikule graben and surroundings, located between the ATF and Karakax faults. Numerous evidences of recent tectonic-related events are present in the vicinity, such as the 1951 volcanic eruption as well as the 2008 and 2014 Ms 7.3 Yutian earthquakes, attesting of its high activity. In addition, the LGCF's en-echelon geometry and identical direction with the ATF, as well as smaller geological offsets and lower slip-rate compared to those on the surrounding faults, suggest that this segment of the ATF may be the most recent.