Early Mesozoic southward migration of Cordilleran transpressional terranes
Early Mesozoic southward migration of Cordilleran transpressional terranes
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早中生代科迪勒拉断压地体向南迁移
DOI：
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发表时间：
1988
期刊：
影响因子：
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通讯作者：
J. Oldow
中科院分区：
文献类型：
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作者：
H. A. Lallemant;J. Oldow
斜向板块会聚作用可使活动边缘造山带的弧前、弧和弧后区域相对于毗邻的大陆和大洋岩石圈板块表现为半独立的板块。这些岩石，这里称为“压扭岩”，一边是俯冲带，另一边是弧前、火山弧或弧后地区的弧平行走滑断层，下面是贯穿的基底滑脱。这些岩石在垂直于俯冲带的方向上缩短，并作为连贯的结构体沿沿着边界走滑断层平行于俯冲带迁移。北美科迪勒拉山脉的许多分支可能都是以这种方式行事的，也许它们并没有穿越太平洋盆地，而是一直在北美的外围。我们建议，在三叠纪至白垩纪中期，部分科迪勒拉边疆一般向南位移相对于北美克拉通由于左斜收敛。白垩纪中期以来，由于右斜俯冲作用，它们向北迁移。建议的位移是一致的构造，古地磁，古生物数据和相对和绝对运动的北美和太平洋盆地板块的热点参考框架模型的基础上。
Oblique plate convergence can cause forearc, arc, and back arc regions of active margin orogenic belts to behave as semi-independent terranes relative to bordering continental and oceanic lithospheric plates. These terranes, called here “transpressional terranes,” are bound by the subduction zone on one side, by arc-parallel strike-slip faults in the forearc, in the volcanic arc, or in the back arc region on the other and are underlain by throughgoing basal decollements. These terranes undergo shortening in a direction perpendicular to the subduction zone and migrate as coherent structural bodies parallel to the subduction zone along bounding strike-slip faults. Many terranes of the North American Cordillera may have behaved in this manner and perhaps did not travel across the Pacific basin but rather were always peripheral to North America. We propose that during the Triassic to mid-Cretaceous, portions of the Cordillera borderland generally were displaced southward with respect to the North American craton due to left-oblique convergence. Since the mid-Cretaceous, they moved northward due to right-oblique subduction. The proposed displacements are consistent with structural, paleomagnetic, and paleontologic data and with the relative and absolute motions of North America and the Pacific basin plates based on hotspot reference frame models.