Seawater cycled throughout Earth's mantle in partially serpentinized lithosphere
Seawater cycled throughout Earth's mantle in partially serpentinized lithosphere
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DOI：
10.1038/ngeo2902
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发表时间：
2017-03-01
影响因子：
18.3
通讯作者：
Perfit, M. R.
中科院分区：
文献类型：
--
作者：
Kendrick, M. A.;Hemond, C.;Perfit, M. R.
在何种程度上水和卤素在地球的地幔有原始的起源，或占主导地位的海水衍生成分引入俯冲是有争议的。地球地幔中约90%的非放射性氙来自俯冲大气，但大气气体和其他海水成分在俯冲过程中的耦合程度尚不清楚。在这里，我们提出了水和卤素的岩浆玻璃样品中的浓度从全球范围内收集的迈阿密海脊和海洋岛屿。我们发现，水和卤素富集意外地与微量元素特征的脱水洋壳，和最不相容的卤素有相对统一的丰度比，是不同的原始地幔值。两者合计，这些结果意味着，地球的地幔是高度加工和大部分的水和卤素被引入的蛇纹岩岩石圈地幔与脱水的洋壳俯冲。
The extent to which water and halogens in Earth's mantle have primordial origins, or are dominated by seawater-derived components introduced by subduction is debated. About 90% of non-radiogenic xenon in the Earth's mantle has a subducted atmospheric origin, but the degree to which atmospheric gases and other seawater components are coupled during subduction is unclear. Here we present the concentrations of water and halogens in samples of magmatic glasses collected from midocean ridges and ocean islands globally. We show that water and halogen enrichment is unexpectedly associated with trace element signatures characteristic of dehydrated oceanic crust, and that the most incompatible halogens have relatively uniform abundance ratios that are different from primitive mantle values. Taken together, these results imply that Earth's mantle is highly processed and that most of its water and halogens were introduced by the subduction of serpentinized lithospheric mantle associated with dehydrated oceanic crust.