青川断裂带中段断层泥中石英颗粒表面微形貌特征及其年代学意义 |
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关键词:Qingchuan Fault Zone fault gouge micromorphology of quartz slip mode activity time |
基金项目:国家自然科学基金(编号: 41472178);中国地质调查局地质调查项目(编号: 1212011120167; 12120114002211) |
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摘要: |
Micromorphology of Quartz in Fault Gouge from the Middle Segment of the Qingchuan Fault Zone and Its Chronological Implications |
Fault gouge, as the product of the brittle shear deformation in fault zone, records the information of fault slipping mode and activity time. The micromorphology textures of quartz in fault gouge, in particular, can be used to semi-quantitatively estimate a relative time of fault activity. The Qingchuan fault, as the southern boundary of the Qinling Tectonic Belt, has been of right-lateral strike-slip since late Cenozoic, and the complete fracture zone including well-developed fault gouge is exposed along the fault. In this paper, the authors chose the pewter gravelly fault gouge and purple fault gouge from the middle segment of Qingchuan Fault Zone (Muyu-Da’an segment) as the study objects on the basis of field investigation, with the emphasis placed on the SEM (scanning electron microscope) observation for surface textures of quartz grains. The quartz micromorphology shows two categories of medium-strong dissolved morphology (II and III) and one type of weak dissolved morphology (Ia) in purple fault gouge, with no rupturing morphology observed. This statistical result indicates that the latest activity time of the middle segment of Qingchuan fault was in late Pleistocene, and no obvious activity happened in Holocene. This viewpoint is well consistent with structural geomorphology investigations along the active fault zone. |
LI Jian,ZHANG Yue-qiao,WU Tai-ran,LI Hai-long,XIONG Jin-hong,LI Jian-hua.2016.Micromorphology of Quartz in Fault Gouge from the Middle Segment of the Qingchuan Fault Zone and Its Chronological Implications[J].Acta Geoscientica Sinica,37(2):153-162. |
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