东昆仑断裂东端塔藏断裂压剪活动与高原隆升作用讨论

发布时间：2018-04-30 22:35

本文选题：塔藏断裂 + 东昆仑断裂带　；参考：《地质学报》2017年07期

【摘要】：塔藏断裂位于东昆仑断裂带东端,横贯青藏高原东缘的高原内部和边缘,因属于巴颜喀拉块体向东南运移的东北侧边界带,其晚第四纪活动性质和滑动速率对认识青藏高原的构造变形模式极端重要。本文综合SPOT、中巴资源卫星等高分辨率遥感影像解译,利用冲沟、山脊、断错河流阶地、断层槽谷、反向坎等地震地貌的识别,开展详细的断错地层、地貌研究和系列年代学样品采集测试,对塔藏断裂的精细几何展布、晚第四纪活动性质、滑动速率进行详细分析。塔藏断裂自西向东可分为青藏高原内部的罗叉段、青藏高原边缘的东北村段和马家磨段,各段走向依次为113°、142°、130°,逐渐向南偏转,晚第四纪的活动表现为分段性和多期性。罗叉段全新世以左旋剪切走滑为主兼挤压活动,左旋走滑速率为2.43~2.89mm/a左右,最新地表断错事件发生在0.66±0.04ka BP以来,断层面表现出走滑断层的近垂直和张裂并发育充填楔的典型特征,塔藏断裂为东昆仑断裂系东延的主要断裂之一;马家磨段也为全新世活动断层,距今9.0±0.8ka的地层被断错,而且断层面北倾达58°。因此,对比分析塔藏断裂各段活动特征可见,西部以水平剪切运动为主,而东部走滑运动分量逐渐变弱,断面北倾、北盘上升导致的垂向分量逐渐变大。东昆仑断裂带及塔藏断裂晚第四纪走滑速率向东规则减小,并转化为横向逆冲作用和高原隆升,符合"叠瓦状逆冲转换—有限挤出模型"的特征。
[Abstract]:The Ta-Zang fault is located at the eastern end of the East Kunlun fault zone, and traverses the interior and edge of the plateau in the eastern margin of the Qinghai-Xizang Plateau, because it belongs to the northeast boundary zone of the Bayankala block moving to the southeast. The late Quaternary activity and slip rate are extremely important for understanding the tectonic deformation model of the Qinghai-Xizang Plateau. In this paper, SPOT, CBERS and other high-resolution remote sensing images are used to identify the seismic landforms, such as gullies, ridges, faulted river terraces, fault troughs, reverse ridges, and so on, to carry out detailed faulted strata. Geomorphological study and collection and measurement of a series of chronological samples, detailed analysis of the fine geometric distribution of the Ta-Zang fault, the late Quaternary active properties and the sliding rate are carried out in detail. From west to east, the Tazang fault can be divided into Luochi section, northeast village section and Majiamo section of the Qinghai-Tibet Plateau margin. The strike of each segment is 113 掳~ 142 掳~ (130 掳), gradually deflecting southward, and the late Quaternary activities are piecewise and multi-period. In the Holocene of Luochi formation, the left-lateral shear strike-slip is dominant and compressional, and the left-lateral strike-slip rate is about 2.43~2.89mm/a. The latest surface fault events occurred since 0.66 卤0.04ka BP. The fault plane shows the typical characteristics of the runaway slip fault near vertical and extensional faults and the development of filling wedge. The Tazang fault is one of the main faults in the east extension of the East Kunlun fault system, and the Majiamo formation is also a Holocene active fault. The stratum of 9.0 卤0.8ka is faulted and the fault plane dips northward to 58 掳. Therefore, by comparing and analyzing the active characteristics of each segment of the Ta-Zang fault, it can be seen that the west is dominated by horizontal shear movement, while the component of the eastern strike-slip motion becomes weaker, the section tilts northward, and the vertical component caused by the rise of the north face gradually becomes larger. The late Quaternary strike-slip rate of the East Kunlun fault zone and the Ta-Tibet fault decreases eastward and is transformed into transversal thrusts and uplift of the plateau, which accords with the characteristics of "imbricate thrust-transformation finite extrusion model".
【作者单位】：中国地震局地震预测重点实验室地震预测研究所;中国地震局第一监测中心;山东省地震局;
【基金】：国家自然科学基金项目(编号41302171、41272233) 国家重点基础研究发展计划(编号2008CB42570) 地震预测研究所基本科研业务经费(编号2017IES0302、2017IES010204)联合资助成果
【分类号】：P542

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