Effect of Water on Subduction of Continental Materials to the Deep Earth
The flows in the subduction channels with wet mantle wedge are calculated by 1-D finite difference method with fine numerical resolutions. The water content largely affects the viscosity of the mantle wedge. Previous simulation result using dry rheology on the mantle wedge shows that viscosity of the subduction channels controls the process and that the sustainable thickness of the channel in the deep mantle is ~2–3 km. However, little is known about the effect of the water content in the mantle wedge on the subduction channels. Here, in order to estimate the supply rate of continental materials to the deep mantle with water-rich environment on the mantle wedge, we have conducted a numerical simulation of a subduction channel. The results show that the water content controls the flux of the continental materials especially when temperature of mantle wedge is high. Therefore, the water content of the mantle wedge can be more important in the ancient mantle because of its high temperature.
KeywordsSubduction erosion Sediment subduction Subduction channel Ultrahigh-pressure metamorphic rocks
The authors thank Dr. Taras Gerya and Dr. Frédéric Deschamps for their useful comments. This study was supported by Global COE program “DEEP EARTH MINERALOGY” and KAKENHI 22740297 and 24840020. Several figures have been realized using matplotlib [Hunter 2007].
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