Effects of relative plate motion on the deep structure and penetration depth of slabs below the Izu-Bonin and Mariana island arcs
Effects of relative plate motion on the deep structure and penetration depth of slabs below the Izu-Bonin and Mariana island arcs
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DOI：
10.1016/0012-821x(93)90253-6
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发表时间：
1993-12
影响因子：
5.3
通讯作者：
R. Hilst;T. Seno
中科院分区：
文献类型：
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作者：
R. Hilst;T. Seno
越来越多的地震学研究表明，俯冲岩石圈板片穿透某些岛弧下方的地球下地幔，但在其他岛弧下方的过渡带中发生偏转，或者更确切地说，沉积在过渡带中。最近对地幔流的数值模拟也主张采用间歇性分层的混合形式的地幔对流。我们对板片形态和地幔动力学进行了多学科分析，其中我们明确地解释了特定岛弧以下的俯冲历史，试图了解是什么控制着板片形态和穿透深度的横向变化。我们讨论的核心是伊豆-小笠原和马里亚纳俯冲带。我们认为，这些俯冲带构造演化的差异，特别是海沟迁移的数量和速度，可以解释为什么俯冲海洋岩石圈板片似乎（至少暂时）停滞在伊豆-博宁岛弧下方的地球过渡带中，但却渗透到马里亚纳岛弧下方的下地幔中。我们简要推测了板片形态时空演化模型对其他俯冲带的适用性。尽管进一步的研究是必要的，但我们的初步模型显示了通过考虑所涉及的俯冲带的板块构造历史来解释板状结构地震图像的潜力。因此，我们希望这里概述的想法能够刺激和指导新的研究举措。
An increasing number of seismological studies indicate that slabs of subducted lithosphere penetrate the Earth's lower mantle below some island arcs but are deflected, or, rather, laid down, in the transition zone below others. Recent numerical simulations of mantle flow also advocate a hybrid form of mantle convection, with intermittent layering. We present a multi-disciplinary analysis of slab morphology and mantle dynamics in which we account explicitly for the history of subduction below specific island arcs in an attempt to understand what controls lateral variations in slab morphology and penetration depth. Central in our discussion are the Izu-Bonin and Mariana subduction zones. We argue that the differences in the tectonic evolution of these subduction zones—in particular the amount and rate of trench migration—can explain why the slab of subducted oceanic lithosphere seems to be (at least temporarily) stagnant in the Earth's transition zone below the Izu-Bonin arc but penetrates into the lower mantle below the Mariana arc. We briefly speculate on the applicability of our model of the temporal and spatial evolution of slab morphology to other subduction zones. Although further investigation is necessary, our tentative model shows the potential for interpreting seismic images of slab structure by accounting for the plate-tectonic history of the subduction zones involved. We therefore hope that the ideas outlined here will stimulate and direct new research initiatives.