Elemental and Isotopic Chloride Geochemistry and Fluid Flow in the Nankai Trough
Elemental and Isotopic Chloride Geochemistry and Fluid Flow in the Nankai Trough
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DOI：
10.1029/2001gl014122
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发表时间：
2002-07
影响因子：
5.2
通讯作者：
A. Spivack;M. Kastner;B. Ransom
中科院分区：
文献类型：
--
作者：
A. Spivack;M. Kastner;B. Ransom
本文给出了南海海槽增生棱柱体和俯冲带变形前缘的第一条孔隙流体Cl−剖面和该环境中的第一条Cl同位素剖面。这表明，在变形锋弧向的大部分剖面和变形锋最低的向海剖面中，存在渠化的水平幕式流动。在下冲断层沉积物中，河道似乎是连续的。根据Cl−梯度，通道内的流体速度为13 ± 5cm/年。深度积分流动和孔隙流体俯冲的接近平衡表明流动事件是频繁的。δ 37 Cl值低于整个剖面的海水，平均值为-6.1 ‰。这表明Cl的流体/矿物交换，并表明俯冲固体携带富集的δ 37 Cl，从俯冲带的更深层次有效地再循环回到海水中，可能是海水/地幔δ 37 Cl分馏的原因。
The first transect of pore fluid Cl− profiles across the deformation front of an accretionary prism and underthrust section, Nankai Trough, and the first Cl isotopic profile in this environment are presented. These demonstrate that there is channelized horizontal episodic flow through most of the section arcward of the deformation front and in the lowermost section seaward of the deformation front. In the underthrust sediments, channels appear to be continuous. Fluid velocities, within the channels, based on Cl− gradients, are 13 ± 5cm/year. The near balance of depth‐integrated flow and the subduction of pore fluid indicates that flow episodes are frequent. δ37Cl values are lower than seawater throughout the section, averaging −6.1 per mil. This demonstrates fluid/mineral exchange of Cl and suggests that subducted solids carry enriched δ37Cl that is efficiently recycled from deeper levels in the subduction zone back into seawater and may be responsible for the seawater/mantle δ37Cl fractionation.