多层滑脱条件下褶皱—冲断带形成制约因素研究:以川东—雪峰构造带为例  

Study on Restrictive Factor of Fold-thrust Belt Formation with Multiple Decollements:Taking Eastern Sichuan-Xuefeng Tectonic Belt as an Example

作　　者：刘重庆[1] 周建勋[1] 郎建[1] 

机构地区：[1]中国石油大学(北京)油气资源与探测国家重点实验室,北京102249

出　　处：《地球科学与环境学报》2013年第2期45-55,共11页Journal of Earth Sciences and Environment

基　　金：国家自然科学基金项目(408721431)

摘　　要：为了研究滑脱层性质对多层滑脱变形系统构造样式及演化过程的影响,设计了3组剖面模型,针对滑脱层流变学性质及其深度对上覆地层构造变形的影响进行物理模拟研究,并结合川东—雪峰构造带褶皱-冲断带实际地质条件进行对比分析。结果表明:滑脱层流变学性质影响上覆地层应变调节方向;水平累积性收缩滑脱层控制下的地层变形具有较大水平应变分量,使得应力快速、大范围传递,形成宽缓的褶皱-冲断带;高流变性滑脱层控制下的地层变形具有显著的垂向运动,形成的褶皱-冲断带狭窄且具有较大锥度;滑脱层深度影响上覆地层褶皱的波长,深层滑脱形成大波长褶皱,紧密排列组合成隔槽式褶皱;浅层滑脱易形成高陡背斜,稀疏分布组合成隔挡式褶皱;川东—雪峰构造带不同区域沉积盖层厚度、滑脱层数量、滑脱深度的差异及南东—北西向挤压应力是形成该区隔挡式、隔槽式褶皱的主控因素。In order to study the impact of properties of decollement layer on the tectonic style and evolution of multiple decollements system, three sets of cross-sectional model were designed, and the impacts of rheological property and depth of decollement on the tectonic deformation of overlying strata were physically simulated, and the simulation result was contrasted with the geological condition of fold-thrust belt in the eastern Sichuan-Xuefeng tectonic belt. The results showed that the rheological properties of decollement layer affected the direction of strain adjustment of overlying strata; the strata deformation under the influence of horizontal cumulative contraction decollement layer had more horizontal components of strain, so that the stress transmitted rapidly and widely, and the wide and gentle fold-thrust belt developed; the direction of strata deformation under the influence of high rheological decollement layer was significant vertical movement, and the narrow fold-thrust belt developed with large taper angle; the depth of decollement layer controlled the wavelength of overlying strata fold, the fold with large wavelength controlled by deep decollement distributed tightly and developed as trough-likefold; high-steep anticline controlled by shallow decollement distributed sparsely and developed as partition style fold~ the sedimentary cover thickness, quantity of decollement layer and decollement depth in different areas and the SE-NW-trending extrusion stress were the key factors for the development of partition style fold and trough-like fold in the eastern Sichuan- Xuefeng tectonic belt.

关 键 词：多层滑脱 隔挡式褶皱 隔槽式褶皱 褶皱波长 构造演化 形成机制 物理模拟 

分 类 号：P542[天文地球—构造地质学]