| 川东多套滑脱层褶皱构造带形成物理模拟 |
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| 引用本文： | 吴航,邱楠生,常健,张纪新,王晔.川东多套滑脱层褶皱构造带形成物理模拟[J].地球科学,2019,44(3):784-797. |
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| 作者姓名： | 吴航 邱楠生 常健 张纪新 王晔 |
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| 作者单位： | 1.中国石油大学油气资源与探测国家重点实验室, 北京 102249 |
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| 基金项目： | 国家自然科学基金项目41690133北京市领军人才项目Z171100001117163国家科技重大专项2016ZX05007-003 |
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| 摘 要： | 川东地区发育典型的"侏罗山式"褶皱构造带，以北东走向的齐岳山断裂为界，南东侧为隔槽式褶皱，北西侧为隔挡式褶皱.中生代川东地区经历了自南东向北西的陆内递进变形，受多套滑脱层（基底拆离面、下寒武统页岩、志留系泥页岩和三叠系膏盐）的共同控制.但是，关于川东褶皱带的形成机制及其整体和分段形成时间仍存在较大争议.应用构造物理模拟方法，再现了川东"侏罗山式"褶皱带的形成过程，并分析了先存断裂及其倾角对川东褶皱构造变形的影响.模拟结果表明，川东褶皱带是齐岳山断裂、华蓥山断裂、志留系滑脱层和基底拆离面组成的阶梯状体系在构造挤压下发生断层相关褶皱作用的结果.基底拆离面（深度约16 km）控制隔槽式褶皱的发育，志留系页岩主要控制隔挡式褶皱的形成.中生代（165~75 Ma）川东地区的构造缩短率约为32%.齐岳山断裂是隔槽式褶皱向隔挡式褶皱过渡的重要枢纽，是先存高角度断裂浅部向北西迁移后的产物.华蓥山断裂的倾角控制着隔挡式褶皱的波长，当倾角较陡时（45°）更有利于发育典型的隔挡式褶皱.
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| 关 键 词： | 川东褶皱带 形成机制 构造物理模拟 齐岳山断裂 华蓥山断裂 构造地质 |
| 收稿时间： | 2018-09-20 |
Physical Simulation on Development of Multilayer Detachment Fold Belt in Eastern Sichuan |
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| Abstract: | Jura-type folds are well-developed in the eastern Sichuan fold-thrust belt, which are separated into two areas with different structural styles by the northeast-trending Qiyueshan fault, ejective folds to the northwest and trough-like folds to the southeast.The tectonic deformation of the Mesozoic intra-continental structural belt is progressive from southeast to northwest and controlled by multiple detachment layers which are the basement decollement horizon, lower-Cambrian shale, Silurian shale and Triassic gypsum-rock, respectively.However, there is still much controversy about the formation mechanism of the eastern Sichuan fold belt and its overall and segmentation formation time.Based on tectonic physical simulation, we reproduced the formation of the Jura-type folds in eastern Sichuan and analyzed the influence of pre-existing fault and fault dips on the tectonic deformation of the eastern Sichuan fold belt.The simulation results show that the eastern Sichuan fold belt is the product of fault-related folding caused by tectonic extrusion in the step system composed of Qiyueshan fault, Huayingshan fault, basement decollement horizon and Silurian detachment layer.The basement decollement horizon (depth of~16 km) results in trough-like folds, while the Silurian shale leads to ejective folds.The structural shortening rate of Mesozoic (about 165-75 Ma) in eastern Sichuan is about 32%.The Qiyueshan fault is an important hinge for the transition from trough-like folds to ejective folds, and is the product of migration of the shallow part of this high-angle fault to the northwest.The steep-dipping Huayingshan fault determines the wavelength of folds, favoring the development of typical ejective folds. |
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