Block rotation by strike-slip faulting: Structural and paleomagnetic evidence
Block rotation by strike-slip faulting: Structural and paleomagnetic evidence
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DOI：
10.1029/jb089ib07p06256
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发表时间：
1984-07
影响因子：
--
通讯作者：
H. Ron;R. Freund;Z. Garfunkel;A. Nur
中科院分区：
文献类型：
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作者：
H. Ron;R. Freund;Z. Garfunkel;A. Nur
几何分析表明，走滑断层组的运动应引起块体旋转；否则，扭曲的断层域将无法与其周围环境相适应。块体旋转方向取决于断层滑移方向以及断层的间距和方向，所有这些都可以从构造数据中获得。然后可以通过古地磁测量来独立测试几何模型的预测。该模型在以色列北部进行了测试。构造数据揭示了同时期右旋和左旋走滑断层的几个区域。古地磁测量表明，在北北西向左旋断层区域，地块顺时针旋转了23.3°±8.2°，在右旋断层区域，地块逆时针旋转了22.4°±9.0°。这些结果与结构几何分析的预测一致。该区域的不均匀变形的综合结果类似于纯剪切，允许 N-S 延伸约 1.3。在其他域中，发现了34.6°±9.1°和53.1°±11.0°的旋转。根据脆性破坏理论，在其原始方向上，左侧和右侧断层以 60°–70° 的角度相交，包围缩短的主轴线。由于块旋转，这个角度现在更大，可能达到 110°。结果表明，在走滑断层域中，不同意义上的大块体旋转。独立的构造和古地磁数据可以在简单的几何模型的框架内进行解释。以色列北部被认为是这种有效板内变形机制的良好模型，预计这种变形也会发生在其他地方类似的构造环境中。
Geometric analysis shows that motion of sets of strike-slip faults should cause block rotation; otherwise the distorted fault domain would not fit with its surrounding. The sense of the block rotation depends on the sense of fault slip and the spacing and orientation of the faults, all of which can be obtained from structural data. The predictions of the geometric model can then be independently tested by paleomagnetic measurements. The model was tested in northern Israel. Structural data reveal several domains of contemporaneous right- and left-lateral strike-slip faults. Paleomagnetic measurements show that in a domain of NNW trending left-lateral faults, blocks rotated 23.3°±8.2° clockwise, and in a domain of right-lateral faults, blocks rotated 22.4°±9.0° anticlockwise. These results are in agreement with the prediction of the geometric analysis of the structure. The combined results of the heterogenous deformation of the area resembles a pure shear which allows N-S extension by about 1.3. In other domains, rotations of 34.6°±9.1° and 53.1°±11.0° were found. In their original orientation the left- and right-lateral faults intersected at angles of 60°–70°, enclosing the principal axis of shortening, in accordance with theories of brittle failure. As a result of block rotations, this angle is now larger and may reach 110°. The results demonstrate large block rotations, in different senses, in domains of strike-slip faults. The independent structural and paleomagnetic data can be interpreted within the framework of a simple geometric model. Northern Israel is considered to be a good model for this efficient mechanism of intraplate deformation, which is expected to occur in similar tectonic settings elsewhere.