Wet subduction versus cold subduction
Wet subduction versus cold subduction
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DOI：
10.1029/2005gl022921
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发表时间：
2005-07-13
影响因子：
5.2
通讯作者：
Funakoshi, K
中科院分区：
文献类型：
--
作者：
Litasov, KD;Ohtani, E;Funakoshi, K
对含水橄榄岩 (2 wt.% H2O) 后尖晶石转变的原位 X 射线衍射研究表明，在 1473 K 时，相对于无水橄榄岩，相界向更高压力移动了 0.6 GPa，而在 1873 K 左右的高温下则没有明显的变化。边界的线性方程为 P (GPa)=-0.002 T (K)+26.3，即适用于低于 1800 K 的温度。目前的数据表明，在 660 公里地震间断面中看到的凹陷的很大一部分可能受到水存在的影响。也很好地解决了与410公里地震不连续性相对应的橄榄石-瓦兹利石相变通过添加水而向较低压力移动1-2 GPa。因此，与板块相关的过渡带地震不连续性的地形不仅可以归因于冷俯冲，还可以归因于湿俯冲。
In situ X-ray diffraction study of post-spinel transformation in hydrous peridotite (2 wt.% H2O) indicates that the phase boundary is shifted to higher pressures by 0.6 GPa relative to anhydrous peridotite at 1473 K, whereas, it shows no obvious shift at high temperature around 1873 K. A linear equation for the boundary is P (GPa)=-0.002 T (K)+26.3, which is applicable for temperatures below 1800 K. The present data shows that a significant part of the depressions seen in the 660-km seismic discontinuity may be affected by existence of water. It is also well resolved that the olivine-wadsleyite phase transformation corresponding to the 410-km seismic discontinuity is shifted to lower pressures by 1-2 GPa by the addition of water. Thus, the topography of seismic discontinuities in the transition zone associated with slabs can be attributed not only to cold subduction but also wet subduction.