Ridge subduction sparked reorganization of the Pacific plate‐mantle system 60–50 million years ago
Ridge subduction sparked reorganization of the Pacific plate‐mantle system 60–50 million years ago
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DOI：
10.1002/2015gl063057
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发表时间：
2015-03
影响因子：
5.2
通讯作者：
M. Seton;N. Flament;J. Whittaker;R. Müller;M. Gurnis;D. Bower
中科院分区：
文献类型：
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作者：
M. Seton;N. Flament;J. Whittaker;R. Müller;M. Gurnis;D. Bower
以太平洋板块为中心的重组发生在约5300万至4700万年前。一个“自上而下”的板块构造机制，Izanagi板块的完全俯冲，而不是“自下而上”的地幔流动机制，被认为是主要的驱动力。根据海洋地球物理观测进行核实是不可能的，因为记录这一事件的大多数洋壳已经俯冲。使用正演模拟方法，将表面板块速度和板片的浅层热结构同化到地幔流模型中，我们表明，Izanagi板块完全俯冲和边缘板片拆离引起了亚太平洋地幔流的重大变化，从60 Ma前的主要向南到50 Ma后的东北偏北。我们的结果与陆上地质，地幔层析成像和夏威夷热点的推断运动一致，并且与60至50 Ma之间太平洋半球快速板块-地幔重组的板块构造过程一致。这种重组反映在太平洋及其周围海洋盆地的构造变化中。
A reorganization centered on the Pacific plate occurred ~53–47 million years ago. A “top‐down” plate tectonic mechanism, complete subduction of the Izanagi plate, as opposed to a “bottom‐up” mantle flow mechanism, has been proposed as the main driver. Verification based on marine geophysical observations is impossible as most ocean crust recording this event has been subducted. Using a forward modeling approach, which assimilates surface plate velocities and shallow thermal structure of slabs into mantle flow models, we show that complete Izanagi plate subduction and margin‐wide slab detachment induced a major change in sub‐Pacific mantle flow, from dominantly southward before 60 Ma to north‐northeastward after 50 Ma. Our results agree with onshore geology, mantle tomography, and the inferred motion of the Hawaiian hot spot and are consistent with a plate tectonic process driving the rapid plate‐mantle reorganization in the Pacific hemisphere between 60 and 50 Ma. This reorganization is reflected in tectonic changes in the Pacific and surrounding ocean basins.