Analogue modelling of faulting in zones of continental transpression and transtension
Analogue modelling of faulting in zones of continental transpression and transtension
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大陆压扭带断层作用的模拟模拟
DOI：
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发表时间：
1998
期刊：
影响因子：
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通讯作者：
B. Colletta
中科院分区：
文献类型：
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作者：
G. Schreurs;B. Colletta
摘要 进行了模拟大陆变形和变形区域变形的实验。分层模型由覆盖一层薄薄的粘性材料的脆性模拟材料组成。倾斜变形是通过将底部分布的走滑剪切分量与横向缩短（变形）或横向延伸（变形）相结合而获得的。在压压实验中，施加的剪切应变率和缩短应变率之比对模型脆性层中的初始断层演化具有重要的控制作用。在应变率相对较高（≥3.6）的实验中，首先发育近垂直的雁列走滑断层，与剪切方向成25-37°角。随着应变的增加，形成了几个会聚的走滑断层带，显示出正花结构。在低应变率比实验（≤2.7）中，平缓倾斜（30-45°）、向下会聚的逆冲断层适应初始破坏。它们限制了平行于剪切方向的弹出结构。应变增加导致断层模式以斜滑逆断层为主。当走滑断层在弹出构造内形成时，断层运动的部分分割发生在应变的后期。走滑断层在深部与围护斜滑逆断层融合，俯视呈曲线形，倾角方向沿走向变化。故障模式可以用作运动学指标。恩梯状走滑断层最初在变张实验中适应变形，并以与剪切方向的小角度（6-10°）走向。随着应变的增加，正断层与较古老的走滑断层平行形成。它们的形成是断层运动和重力破坏分开的结果。实验结果与大陆压扭和张拉构造的自然实例之间有很好的一致性。
Abstract Experiments were performed to simulate deformation in zones of continental transpression and transtension. Stratified models consisted of brittle analogue materials overlying a thin layer of viscous material. Oblique deformation was obtained by combining a basal, distributed strike-slip shear component with either transverse shortening (transpression) or transverse extension (transtension). In transpression experiments the imposed ratio of shear strain rate and shortening strain rate exerts an important control on initial fault evolution in the brittle layers of the model. In those experiments with a relatively high strain rate ratio (≥3.6), subvertical, en echelon strike-slip faults develop first, striking at angles of 25–37° to the shear direction. With increasing strain several convergent strike-slip fault zones form displaying positive flower structures. In low strain rate ratio experiments (≤2.7), gently dipping (30–45°), downward converging thrust faults accommodate initial failure. They bound pop-up structures that strike parallel to the shear direction. Increasing strain results in a fault pattern dominated by oblique-slip reverse faults. Partial partitioning of fault motion occurs at late stages of strain when strike-slip faults form within popup structures. The strike-slip faults merge at depth with confining oblique-slip reverse faults, have a curved shape in plan view and a dip direction which changes along strike. Fault patterns can be used as kinematic indicators. En echelon strike-slip faults initially accommodate deformation in a transtension experiment and strike at low angles (6–10°) to the shear direction. With increasing strain, normal faults form parallel to older strike-slip faults. They develop as a result of partitioning of fault motion and gravity failure. There is good agreement between experimental results and natural examples of continental transpressional and transtensional tectonics.