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多滑脱层构造物理模拟试验及其对川东褶皱带形成演化的指示意义 |
裴仰文1,盛受政1,苗正硕1,牟毅城1,苏楠2,郭伟2,冯犇1,王静1,梁瀚3,谢柳娟4
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(1.中国石油大学(华东)地球科学与技术学院,山东青岛 266580;2.中国石油天然气股份有限公司勘探开发 研究院,北京 100083;3.中国石油天然气股份有限公司西南分公司勘探开发研究院,四川成都 610041;4.中国地质调查局青岛海洋地质研究所,山东青岛 266071)
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摘要: |
通过多滑脱层砂箱模拟试验探讨川东地区3套滑脱层对川东褶皱带形成演化过程的控制作用。结果表明:滑脱层纵向配置和变形速率对多套滑脱层发育区的构造变形样式及构造演化具有重要控制作用,深部滑脱层的拆离效果显著强于浅部滑脱层,导致垂向上深部构造层之间的构造变形差异性高于浅部构造层,变形速率减小时,滑脱层的拆离效果明显增加,各构造层的变形样式差异性也随之增强;川东地区3套滑脱层对于川东褶皱带的构造变形具有明显的拆离作用,深部的中下寒武统膏盐岩的拆离作用显著强于中浅部的志留系泥岩和中下三叠统膏盐岩,导致川东地区3套构造层的变形特征具有很大的差异;川东地区在早期弱挤压变形阶段(变形速率较低)3套滑脱层拆离作用明显,以发育滑脱褶皱及小型的调节断层为主要构造变形特征,各构造层变形特征产生明显的垂向差异性,在后期强烈挤压变形阶段变形速率快速提升,限制各滑脱层的拆离作用,各构造层以发育高陡逆冲断层和反冲断层为主,变形特征趋于一致。 |
关键词: 川东褶皱带 多滑脱层 砂箱模拟试验 拆离作用 变形速率 |
DOI:10.3969/j.issn.1673-5005.2022.02.004 |
分类号::TE 121 |
文献标识码:A |
基金项目:国家自然科学基金面上项目(41872143);中央高校基本科研业务费专项(19CX02005A) |
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Sandbox physical modelling with multiple detachment layers and its implication on structural evolution of East Sichuan Fold Belt |
PEI Yangwen1, SHENG Shouzheng1, MIAO Zhengshuo1, MOU Yicheng1, SU Nan2, GUO Wei2, FENG Ben1, WANG Jing1, LIANG Han3, XIE Liujuan4
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(1.School of Geosciences in China University of Petroleum (East China), Qingdao 266580, China;2.Research Institute of Petroleum Exploration & Development, PetroChina, Beijing 100083, China;3.Research Institute of Petroleum Exploration & Development, PetroChina Southwest Oil & Gasfield Company, Chengdu 610041, China;4.Qingdao Institute of Marine Geology, China Geological Survey, Qingdao 266071, China)
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Abstract: |
In this research, sandbox physical modelling with multiple detachment layers was employed to study the controlling effects of the three detachment layers in east Sichuan Basin. The sandbox results indicate that the setting (including number and vertical distribution) of detachment layers and deformation rate are of great importance in controlling both the deformation styles and structural evolution. On one hand, the deep detachment layers normally present a higher level of decoupling than the shallow detachment layers, leading to a higher geometric variation in deep section than upper section. On the other hand, the lower deformation rates are, the higher decoupling of the detachment layers becomes, resulting in a higher level of geometric variation between different structural packages. The three detachment layers play a significant role of decoupling in east Sichuan Basin, with a higher level of decoupling by the Lower-Mid Cambrian salt layer in the deep subsurface compared to the Silurian shale and Lower-Mid Triassic salt layer in the shallow subsurface. The structural deformation in east Sichuan Basin is likely geological time-dependent. In the early stage with a weak contraction (low deformation rate), the three detachment layers present a high level of decoupling, resulting in detachment folds and accommodation faults with a significant vertical geometric variation between different structural packages. In the later stage with an intense contraction (high deformation rate), the detachment layers present a limited decoupling, forming high angle thrust faults and back-thrust faults with a higher geometric consistency between different structural packages. |
Key words: Eastern Sichuan Fold Belt multiple detachment layers sandbox physical modelling decoupling deformation rate |