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| 青藏高原东南部第四纪右旋剪切运动 | |
| 引用本文： | 沈军,汪一鹏,任金卫,曹忠权.青藏高原东南部第四纪右旋剪切运动[J].新疆地质,2003,21(1):120-125. |
| 作者姓名： | 沈军 汪一鹏 任金卫 曹忠权 |
| 作者单位： | 1. 新疆维吾尔自治区地震局,乌鲁木齐,新疆,830011;中国地震局地质研究所,北京,100029 2. 中国地震局地质研究所,北京,100029 3. 西藏自治区地震局,西藏,拉萨,850000 |
| 基金项目： | 国家95攀登项目“青藏高原岩石圈现今变动与动力学研究”资助 |
| 摘 要： | 通过对藏东南嘉黎断裂和滇西北断裂实地考察研究，表明青藏高原南部不存在统一的边界走滑断裂。嘉黎断裂的西段位于青藏高原南部，是一个南北挤压作用下的东西向伸展构造区，发育近南北向的地堑系，嘉黎断裂西段是这些地堑之间的转换断层，具有较高的右旋走滑速率。滇西北断裂与红河断裂构成川滇菱形块体的西南边界，该块体具有向东南逃逸和顺时针旋转运动。 |
| 关 键 词： | 第四纪 右旋剪切运动 青藏高原 地球动力学 嘉黎断裂带 遥感 地貌 |
| 文章编号： | 1000-8845(2003)01-120-06 |
| 修稿时间： | 2002年8月1日 |
QUATERNARY DEXTRAL SHEARING AND CRUSTAL MOVEMENT IN SOUTHEAST TIBETAN PLATEAU |
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| Jun Shen,Yi-peng Wang,Jin-wei Ren,Zhong-quan Cao.QUATERNARY DEXTRAL SHEARING AND CRUSTAL MOVEMENT IN SOUTHEAST TIBETAN PLATEAU[J].Xinjiang Geology,2003,21(1):120-125. | |
| Authors: | Jun Shen Yi-peng Wang Jin-wei Ren Zhong-quan Cao |
| Abstract: | One of the most significant late Cenozoic kinetic characteristics of Tibetan plateau is the eastward extrusion of the main body of the Plateau. It is still unknown whether or not an integrate right-lateral strike-slip fault exists in the south of the extrusive massif, just like the Altyn Tagh fault in the northern boundary of the massif. Based on the study of the Jiali fault in southeastern Tibet and Deqin-Zhongdian-Daju fault in northwestern Yunnan province of China, we suggest that the Karakorum fault zone does not extend southeastward to the northwestern Yunnan and connect with Red River fault. There is no integrate boundary strike-slip fault developed in the southern Tibet. The deformation style in the southern Tibet is different from that in north. As a part of the proposed Karakorum-Jiali fault zone in the southern Tibet, the northwestern segment of Jiali fault shows a clear right-lateral strike-slip sense. The average slip rate since the middle Pleistocene is estimated to be 6-8 mm/a and over 10 mm/a since the late Pleistocene along some secondary segments. However, no clear evidences of right-lateral strike-slip were found along the middle and southeastern segments of Jiali fault. The fault extends southeastward to Xia Chayu and connects with Saga fault.The Deqin-Zhongdian-Daju fault is a nascent right-lateral strike-slip fault developed in the northwestern Yunnan since the late Pliocene. A bound of drainage and other offsets were found along the fault. The slip rate is estimated to be around 4~6mm/a since the middle Quaternary. It does not cut through the Hengduan Shan(Mountains) to connect with Jiali fault. It extends northwestward and connects with Lanchangjian fault, which is the western boundary of the Sichuan-Yunnan rhombic block of the eastern Tibetan plateau.The active faults during Quaternary in the eastern syntax of Himalayan mountains are NWN-trending right-lateral strike-slip normal faults, such as Ranwu fault. The NW-trending right-lateral strike-slip faults in northwestern Yunnan do not combine with the WNW trending right-lateral strike-slip faults in the southern Tibet. There is no integrated strike-slip boundary fault in the southern Tibetan plateau.The eastward extrusive block is just a triangle area in northeastern Tibetan plateau which consists of Bayanhala massif and Qiadam massif. The predominant deformation in southern Tibetan Plateau is the E-W extension under the N-S compression. The typical late Cenozoic tectonics in southern Tibetan Plateau is the N-S graben systems and NW-trending right-lateral strike-slip transform faults. The Deqin-Zhongdian-Daju right-lateral strike-slip fault and the Red River right-lateral strike-slip fault in Yunnan compose the southwestern boundary shearing zone of the southeastward escaping rhombic Sichuan-Yunnan block, which is the south part of the eastward extrusive triangle area in northeastern Tibetan Plateau. |
| Keywords: | Tibetan plateau geodynamics Jiali fault Deqin-Zhongdian-Daju fault |
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