Deformation and secondary faulting associated with basement-involved compressional and extensional structures
Deformation and secondary faulting associated with basement-involved compressional and extensional structures
复制标题
DOI：
10.1306/09131010007
复制
发表时间：
2011-04
期刊：
影响因子：
3.5
通讯作者：
James F. Miller;S. Mitra
中科院分区：
文献类型：
--
作者：
James F. Miller;S. Mitra
利用实验粘土模拟方法研究了基底断裂上方变形带的几何特征和演化规律。对反向断层倾斜30、45和60，垂直断层倾斜60和75，正断层变形的性质进行了比较。基底断裂作用导致形成剪切的三角形变形带，在盖层单元中向上加宽。大部分变形集中在次级断层的中心地带，这些次级断层向上传播，最终贯穿整个区段。基本单元的倾角较大，断层密度较高，而地层较高的单元倾角较小，断层密度较低。倾角较小的逆断层，变形带宽度一般较大。对于中低角度逆断层，背斜轴面通常与向斜轴面倾角相同；而对于垂直断层和正断层，轴面倾角则相反。颗粒轨迹表明变形带内存在凸起向上的旋转，表明物质在主断层的延伸处转移。逆断层与具有逆冲和逆冲分离的次级断层伴生。垂直断层主要与垂直和逆行的次生断层有关，而正断层通常与大多数次生断层的正常分隔有关。因此，次级断层的性质随着构造位置的不同而不同，可能在同一层内。这些结果提供了一些关键的见解，对于解释宏观的地表和地下基底相关结构是有用的。
Experimental clay modeling is used to study the geometry and evolution of deformation zones formed above basement faults. The nature of deformation is compared for reverse faults dipping 30, 45, and 60, vertical faults, and normal faults dipping 60 and 75. Basement faulting results in the formation of a sheared triangular deformation zone that widens upward in the cover units. Most of the deformation is focused within a central zone of secondary faults, which propagate upward and eventually break through the entire section. Basal units exhibit steeper dips and higher fault densities, whereas stratigraphically higher units exhibit gentler dips and lower fault densities. The width of the deformation zone is generally greater for reverse faults with low dips. The anticlinal axial surface typically dips in the same direction as the synclinal axial surface for low- to moderate-angle reverse faults; however, the axial surfaces dip in opposite directions for vertical faults and normal faults. Particle paths suggest a convex upward rotation within the deformation zone, suggesting transfer of material across the extension of the master fault. Reverse faults are associated with secondary faults with reverse and thrust separations. Vertical faults are associated with mostly vertical and reverse secondary faults, whereas normal faults are generally associated with normal separation of most secondary faults. Therefore, the nature of secondary faults varies with structural position, possibly within the same layer. These results provide some key insights that are useful in the interpretation of macroscopic surface and subsurface basement–involved structures.