North American dynamics and western U.S. tectonics
North American dynamics and western U.S. tectonics
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北美动力学和美国西部构造
DOI：
10.1029/2005rg000181
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发表时间：
2007
影响因子：
25.2
通讯作者：
D. Coblentz
中科院分区：
文献类型：
--
作者：
E. Humphreys;D. Coblentz
关于板块移动和构造变形的力的起源存在兴趣和争议，特别是关于施加到板块边缘和底部的载荷以及内部产生的载荷（例如，通过隆起区域中升高的势能）的相对重要性。为了量化这些载荷，我们通过北美板块的二维有限元分析来评估预测的板间应力，发现边界载荷最重要，其次是内部载荷和底部载荷。克拉通根部的基底牵引力约为 4 MPa，与绝对板块运动相反，而其他地方的基底牵引力平均约为 0.4 MPa，这表明北美通过弱软流圈与相对静止的深层地幔分开。圣安地列斯剪切力（~1.5 TN/m）、重力塌陷和卡斯卡迪亚南部拉力都对美国西部变形产生了重要影响；该地区也相对较弱。未来的重要工作包括将三维板结构纳入全局流量计算中，并包括全局板组。
Interest and controversy exist on the origin of forces that move and tectonically deform plates, especially regarding the relative importance of loads applied to the plate margins and base and those created internally (e.g., by elevated potential energy in uplifted regions). To quantify these loads, we evaluate predicted interplate stress through two‐dimensional finite element analysis of the North American plate, finding that boundary loads are most important, followed by internal and basal loads. Craton root basal drag of ∼4 MPa opposes absolute plate motion, compared to basal tractions elsewhere that average ∼0.4 MPa, suggesting that North America is separated from a relatively static deep Earth mantle by a weak asthenosphere. San Andreas shear (∼1.5 TN/m), gravitational collapse, and southern Cascadia pull all contribute importantly to western U.S. deformation; the region also is relatively weak. Important future work includes incorporating three‐dimensional plate structure onto global flow calculations and including the global set of plates.