Geodynamic evolution of southwestern North America since the Late Eocene
Geodynamic evolution of southwestern North America since the Late Eocene
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DOI：
10.1038/s41467-019-12950-8
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发表时间：
2019-11-18
影响因子：
16.6
通讯作者：
Holt, William E.
中科院分区：
文献类型：
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作者：
Bahadori, Alireza;Holt, William E.
板块回滚、岩石圈体力或板块边界条件的演化是北美西南部新生代伸展的可能的岩石圈驱动机制。通过结合古地形，岩石圈结构和古海岸条件，我们开发了一个完整的地球动力学模型，量化岩石圈偏应力和预测的伸展和剪切历史，自晚始新世。我们表明，岩石圈体力的影响，从晚始新世到早中新世的俯冲转换到transtensional边界条件的主要驱动因素控制的方向和幅度的拉伸偏应力，产生地形崩塌。在古高地塌陷之后，太平洋-北美板块运动的影响以及沿板块边界沿着的变形方式从中中新世至今变得越来越重要。小规模对流应力的影响，从板卷回滚和相关的地幔流只发挥了次要作用。然而，板坯回滚通过引入熔体和影响流变学的流体来引导变形速率。
Slab rollback, lithospheric body forces, or evolution of plate boundary conditions are strongly debated as possible lithospheric driving mechanisms for Cenozoic extension in southwestern North America. By incorporating paleo-topography, lithospheric structure, and paleoboundary conditions, we develop a complete geodynamic model that quantifies lithospheric deviatoric stresses and predicts extension and shear history since Late Eocene. We show that lithospheric body forces together with influence of change-over from subduction to transtensional boundary conditions from Late Eocene to Early Miocene were the primary driving factors controlling direction and magnitude of extensional deviatoric stresses that produced topographic collapse. After paleo-highlands collapsed, influence of Pacific-North America plate motion and associated deformation style along the plate boundary became increasingly important from Middle Miocene to present. Smaller-scale convection stress effects from slab rollback and associated mantle flow played only a minor role. However, slab rollback guided deformation rate through introduction of melts and fluids that impacted rheology.