Contrasted East Asia and South America tectonics driven by deep mantle flow
Contrasted East Asia and South America tectonics driven by deep mantle flow
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DOI：
10.1016/j.epsl.2019.04.025
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发表时间：
2019-07
影响因子：
5.3
通讯作者：
Ting Yang;Louis Moresi;M. Gurnis;Shaofeng Liu;D. Sandiford;S. Williams;F. Capitanio
中科院分区：
文献类型：
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作者：
Ting Yang;Louis Moresi;M. Gurnis;Shaofeng Liu;D. Sandiford;S. Williams;F. Capitanio
至少从侏罗纪开始，东亚和南美都经历了长期的俯冲，但从晚白垩纪开始，它们的构造演化就截然不同。东亚新生代以伸展构造为主，形成了许多边缘海盆地；南美洲新生代以挤压构造为主，形成了安第斯山脉。控制太平洋两岸构造风格对比的机制尚不清楚。我们认为，地震层析成像、板块重建和地球动力学模型揭示的深部地幔流动是造成泛太平洋构造差异的原因之一。我们的地球动力学模型表明，大西洋的开放通过允许南美洲向海沟的快速运动，在促进挤压主导型构造和沿着南美边缘的安第斯构造中起着重要作用。另一方面，自古生代和中生代早期亚洲组合以来，亚洲内部长期存在的下沉流抑制了亚洲的大西洋型洋开，抑制了东亚向海沟运动，促进了亚洲边缘以伸展为主的构造。受抑制的向海沟运动表明，晚中生代东亚地区发生平板俯冲的可能性较低。
East Asia and South America have both experienced long-term subduction since at least the Jurassic, but they have had contrasting tectonic evolutions since the Late Cretaceous. East Asia was dominated by extensional tectonics with many marginal sea basins forming during the Cenozoic while South America was dominated by compressional tectonics building the Andean mountains. The mechanism controlling this contrast in tectonic style on opposite sides of the Pacific has been unclear. We suggest that the deep mantle flow revealed by seismic tomography, plate reconstructions, and geodynamic models contributed to the pan-Pacific tectonic disparity. Our geodynamic models suggest that the Atlantic Ocean opening plays an important role in promoting compression-dominated tectonics and Andean building along the South American margin by allowing fast trench-ward motion of South America. On the other hand, the long-standing downwelling flow beneath the interior of Asia since Asian assembly in the Paleozoic and the early Mesozoic helps to inhibit Atlantic-type ocean opening in Asia and restrain trench-ward motion of East Asia, promoting extension-dominated tectonics along the Asian margin. The restrained trench-ward motion suggests a low probability of flat-slab subduction occurrence in East Asia during the late Mesozoic.