Supply rate of continental materials to the deep mantle through subduction channels
Supply rate of continental materials to the deep mantle through subduction channels
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DOI：
10.1016/j.tecto.2013.02.001
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发表时间：
2013-04
期刊：
影响因子：
2.9
通讯作者：
H. Ichikawa;K. Kawai;S. Yamamoto;M. Kameyama
中科院分区：
文献类型：
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作者：
H. Ichikawa;K. Kawai;S. Yamamoto;M. Kameyama
地质研究表明，大陆物质通过以下三种机制从地球表面俯冲：构造侵蚀、沉积物俯冲和未成熟洋弧的直接俯冲。然后，大陆物质通过位于俯冲板块和地幔楔形之间的俯冲通道输送。然而，俯冲通道到达的深度以及该深度处俯冲物质的流量大小尚不清楚。在这里，为了估计大陆物质对深部地幔的供应速率，我们基于有限差分方法对俯冲通道进行了数值模拟。我们发现，深部地幔中可持续的航道厚度为~2-3公里，其对应的大陆物质通量在现今俯冲带长度范围内为2.2km~3/年。这些结果表明，几乎所有通过航道俯冲的大陆物质都能够到达地幔过渡带的深度。据估计，4Gyr以上向深部地幔输送的大陆物质总量约为1010km3，大于地球表面现今大陆地壳的体积。
Geological studies have revealed that continental materials subduct from the Earth's surface via the following three mechanisms: tectonic erosion, sediment subduction, and direct subduction of immature oceanic arcs. Then, the continental materials are transported through subduction channels that are located between subducting slabs and mantle wedges. However, the depth that a subduction channel reaches and the magnitude of the flux of subducted materials at that depth are not clear. Here, in order to estimate the supply rate of continental materials to the deep mantle, we have conducted a numerical simulation of a subduction channel based on the finite difference method. We have found that a sustainable thickness of the channel in the deep mantle is ~2–3km and its corresponding flux of continental materials integrated over the length of the current subduction zones is 2.2km3/yr. These results indicate that almost all of the continental material that is subducted through the channel is capable of reaching the depth of the mantle transition zone. The total amount of continental materials conveyed to the deep mantle over 4Gyr is estimated to be about 1010km3, which is greater than the volume of the present continental crust at the surface of the Earth.