| Structural and Geochronological Evidence for Multiple Episodes of Tertiary Deformation along the Ailaoshan-Red River Shear Zone, Southeastern Asia, Since the Paleocene |
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| 作者姓名： | ZHANG Jinjiang ZHONG Dalai SANG Haiqing ZHOU Yong |
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| 作者单位： | [1]The Key Laboratory of Orogenic Belts and Crustal Evolution, Ministry of Education, China ~ School of Earth and Space Sciences, Peking University, Beijing 100871 [2]Institute of Geology and Geophysics, Chinese Academy of Sciences, P. O. Box 9825, Beijin |
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| 摘 要： | Structural analyses show that the Ailaoshan-Red River shear zone （ASRRSZ） in Ailao Mountain is composed of three different deformational domains. These domains may represent three episodes of left-lateral slip experienced by the ASRRSZ. The first episode of such deformation occurred throughout the eastern high-grade belt of the ASRRSZ under a transtensional regime and produced L- type tectonites of amphibolite grade. The second episode of left-lateral slip formed high strain zones overprinting the high-grade belt. Its deformational mechanism is similar to simple shear and the deformed rocks are L-S mylonites of greenschist grade. The third episode of left-lateral slip took place chiefly in a western low-grade belt of the ASRRSZ. This deformation occurred in a transpressional regime, formed an overall structure pattern of a sinistral thrust system and produced phyllonites of low-greenschist grade. Geochronological data indicated that the three episodes of left-lateral slip happened before ～58-56 Ma, at least from ～27 Ma to 22 Ma and at ～13-12 Ma respectively. The first episode of slip in the ASRRSZ appeared to correspond to the initial collision of India and Asia at ～60 Ma. The second episode took place almost at the same time as the most intensive compression and uplift in Tibet. The latest event might represent a further eastward material flow in Tibet after ～16-13 Ma. Thus, the ASRRSZ of southeastern Asia probably experienced three main episodes of Tertiary left- lateral slip in the course of intracontinental convergence since the India-Asia collision.
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| 关 键 词： | 第三纪 变形 扭性 古新世 地质构造 |
| 收稿时间： | 2005-01-21 |
| 修稿时间： | 2005-06-17 |
Structural and Geochronological Evidence for Multiple Episodes of Tertiary Deformation along the Ailaoshan-Red River Shear Zone, Southeastern Asia, Since the Paleocene |
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| Authors: | ZHANG;Jinjiang;ZHONG;Dalai;SANG;Haiqing;ZHOU;Yong |
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| Abstract: | Abstract Structural analyses show that the Ailaoshan‐Red River shear zone (ASRRSZ) in Ailao Mountain is composed of three different deformational domains. These domains may represent three episodes of left‐lateral slip experienced by the ASRRSZ. The first episode of such deformation occurred throughout the eastern high‐grade belt of the ASRRSZ under a transtensional regime and produced L‐type tectonites of amphibolite grade. The second episode of left‐lateral slip formed high strain zones overprinting the high‐grade belt. Its deformational mechanism is similar to simple shear and the deformed rocks are L‐S mylonites of greenschist grade. The third episode of left‐lateral slip took place chiefly in a western low‐grade belt of the ASRRSZ. This deformation occurred in a transpressional regime, formed an overall structure pattern of a sinistral thrust system and produced phyllonites of low‐greenschist grade. Geochronological data indicated that the three episodes of left‐lateral slip happened before ～58–56 Ma, at least from ～27 Ma to 22 Ma and at ～13–12 Ma respectively. The first episode of slip in the ASRRSZ appeared to correspond to the initial collision of India and Asia at ?60 Ma. The second episode took place almost at the same time as the most intensive compression and uplift in Tibet. The latest event might represent a further eastward material flow in Tibet after ～16–13 Ma. Thus, the ASRRSZ of southeastern Asia probably experienced three main episodes of Tertiary left‐lateral slip in the course of intracontinental convergence since the India‐Asia collision. |
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| Keywords: | Ailaoshan-Red River shear zone southeastern Asia geochronology deformation history India-Asia collision |
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