Three-dimensional numerical models of the influence of a buoyant oceanic plateau on subduction zones
Three-dimensional numerical models of the influence of a buoyant oceanic plateau on subduction zones
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DOI：
10.1016/j.tecto.2009.08.021
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发表时间：
2010-03
期刊：
影响因子：
2.9
通讯作者：
W. Mason;Louis Moresi;P. Betts;M. Miller
中科院分区：
文献类型：
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作者：
W. Mason;Louis Moresi;P. Betts;M. Miller
我们用三维数值模式研究了大洋高原-海沟碰撞过程中对俯冲带的潜在影响。在平板中嵌入了不同密度的海洋高原，平板的一端被固定。高原强烈地影响着战壕的形状。对于密度较高的高原，高原周围的沟槽退缩速率减小，高原与板块一起俯冲。对于密度较低的高原，高原区域的海沟向前推进，高原压缩并抵抗俯冲，沿海沟横向扩展。随着板坯流变性的减弱，沟槽朝向沟槽自由端的弧形形状增强。在浮力最大的高原之下，在板块尖端到达下地幔顶部后不久，板块俯冲部分形成了一道撕裂。我们将模型结果与西北太平洋的一个地区进行了比较，在那里小川高原与伊豆-博宁-马里亚纳俯冲带的海沟相遇。
We have investigated potential effects on a subduction zone during oceanic plateau–trench collision, using three-dimensional numerical models. An oceanic plateau of varied density was embedded in the slab, which was pinned at one end. The plateaus strongly influenced the shape of the trench. For a plateau with a higher density, the trench retreat rate was reduced in the region surrounding the plateau, and the plateau subducted along with the slab. For lower density plateaus, the trench in the region of the plateau advanced, and the plateau compressed and resisted subduction, spreading laterally along the trench. With a weaker slab rheology, the arcuate shape of the trench towards the free end of the trench was enhanced. Beneath the most buoyant plateaus, a tear formed in the subducted portion of the slab, soon after the slab tip reached the top of the lower mantle. We compare the model results with a region in the northwest Pacific, where the Ogasawara Plateau meets the trench of the Izu–Bonin–Mariana subduction zone.