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Dynamic topography and lithospheric stresses since 400 Ma

机译：动态地形和岩石层应力自400 mA以来

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摘要

We present a global model of dynamic topography and lithospheric stresses for the last 400 Ma. Our starting point is a simple geodynamic model combining both contributions of subducted lithosphere and long-wavelength upwellings in a reference frame linked to the fixed African plate. A dominant feature of plate tectonics is the quasi permanence of a girdle of subductions around the Pacific Ocean (or its ancestor), which creates large-wavelength positive topography anomaly within the ring they form. The superimposition of the resultant extension with the one induced by the dome leads to a permanent extensional regime over Africa and the future Indian ocean which creates faults with azimuth directions depending on the direction of the most active part of the ring of subductions. We thus obtain fractures with NW-SE azimuth during the period 275-165 Ma parallel to the strike of the subduction zone of the West South American active margin, which appears to be very active during this period. Between 155 and 95 Ma, subduction became more active along the Eastern Australian coast involving a change in the direction of the faults toward an E-W direction, in agreement with the observed fault systems between Africa and India, Antartica and Australia. During the Mesozoic and the Cenozoic, we correlate the permanent extensional regime over Africa and Indian Ocean with the observed rift systems. Finally we emphasize the role of three primary hotspots as local additional contributors to the stress field imposed by our proposed subduction-doming system, which help in the opening of Indian and South Atlantic Oceans.
机译：我们展示了最后400 mA的全球动态地形和岩石层压力模型。我们的起始点是一个简单的地质动力学模型，将化脓性岩石圈和长波长Updweling的贡献相结合，参考框架连接到固定的非洲板。板块构造的主导特征是太平洋（或其祖先）周围的腰带腰带的准持久性，其在它们形成的戒指内产生大波长正极的地形异常。由圆顶诱导的所得延伸的叠加导致非洲的永久性扩展制度和未来的印度洋，这取决于凹凸环的最活跃部分的方向的方位方向产生故障。因此，我们在275-165 mA期间与NW-SE方位角进行了骨折，与西南美国主动边际的俯冲区的击打，这在此期间似乎非常活跃。在155到95 mA之间，俯冲沿东部澳大利亚海岸更加活跃，涉及朝向E-W方向的方向的变化，同意非洲和印度，南澳大利亚之间观察到的故障系统。在中生代和新生代期间，我们将永久性扩展政权与非洲和印度洋与观察到的裂缝系统相关联。最后，我们强调了三个主要热点作为当地额外贡献者对我们拟议的潜水系统所施加的应力领域的额外贡献者，这有助于开幕印度和南大西洋。

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