The kinematics of reactivation of normal faults using high resolution throw mapping
The kinematics of reactivation of normal faults using high resolution throw mapping
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DOI：
10.1016/j.jsg.2008.04.008
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发表时间：
2008-08
影响因子：
3.1
通讯作者：
C. Baudon;J. Cartwright
中科院分区：
文献类型：
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作者：
C. Baudon;J. Cartwright
利用巴西近海的高质量三维地震资料，研究了与新生代碎屑沉积物错开的伸展断层的正常复活。这些断裂形成了复杂的顶部塌陷地堑，是早新生代隆升导致下伏白垩纪层序椭圆隆起的结果。该数据集的卓越质量允许对断层的落差分布进行极其详细的分析。除了重建断层网络的3D几何形状外，这还可以深入了解复活的机制和运动学。从这个数据集中可以识别出两种不同的再激活模式。主要模式是一个经典的复活向上传播的预先存在的结构。第二种模式，称为再激活的倾角联动，是一个单独的故障段的传播开始以上的预先存在的故障，硬链接在倾角方向。对于这两种机制，再激活过程是选择性的，只发生在某些部分的故障。控制某些段优先再活化的因素包括：（1）先存断层面相对于负责再活化的主应力的方向，（2）先存网络的分段和（3）先存断层的最大尺寸和落差值以及与滑脱相关的基底尖端线几何形状。再活化是一个重要的过程，可以解释断层-尺度关系中的部分分散性，应该包括在断层-生长模型中。
Normal reactivation of extensional faults offsetting Cenozoic clastic sediments is investigated using high quality 3D seismic data from offshore Brazil. These faults form complex crestal collapse grabens and result from elliptical doming of the underlying Cretaceous sequence due to Early Cenozoic uplift. The exceptional quality of this dataset allows an extremely detailed analysis of the throw distribution to be conducted on the faults. This, in addition to a reconstruction of the 3D geometry of the fault network, gives insights into the mechanisms and kinematics of reactivation. Two distinct modes of reactivation are recognised from this dataset. The main mode is a classical reactivation by upward propagation of pre-existing structures. A second mode, termed reactivation by dip linkage, is the propagation of an individual fault segment initiated above the pre-existing faults that hard link in the dip direction. For both mechanisms, reactivation processes are selective and only occur on some portions of faults. Factors controlling the preferential reactivation of some segments include: (1) orientation of the pre-existing fault plane relative to the principal stresses responsible for the reactivation, (2) segmentation of the pre-existing network and (3) maximum dimensions and throw values of pre-existing faults and basal tip line geometry associated with a detachment. Reactivation is an important process that may account for part of the scatter in fault-scaling relationships and should be included in fault-growth models.