Dynamic changes in fluid redox state associated with episodic fault rupture along a megasplay fault in a subduction zone
Dynamic changes in fluid redox state associated with episodic fault rupture along a megasplay fault in a subduction zone
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DOI：
10.1016/j.epsl.2010.12.029
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发表时间：
2011-02
影响因子：
5.3
通讯作者：
A. Yamaguchi;S. Cox;G. Kimura;S. Okamoto
中科院分区：
文献类型：
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作者：
A. Yamaguchi;S. Cox;G. Kimura;S. Okamoto
虽然氧化还原态在化学反应中起着重要作用，但在断裂带流体-岩石相互作用过程中却很少受到关注。摘要对日本岛曼托增生杂岩的巨气断裂Nobeoka逆冲碳酸盐岩岩脉进行了地球化学分析（主元素填图和微量元素分析），结果表明地震断裂和流体流动与氧化还原状态的动态突变有关。在地震旋回的破坏前流体加压阶段，沿断裂带运移的流体相对氧化，而在破坏后阶段则相对减少。破坏后还原性热液体系的产生可能与沿大储层断层的孕震破裂有关，涉及来自更深层次的外来还原性流体的平流或通过同震力学化学反应原位生成氢气。
Although redox state plays an important role in chemical reactions, it has received little attention in terms of processes of fluid–rock interaction in fault zones. The results of geochemical analyses (major element mapping and trace element analyses) of carbonate veins along the Nobeoka Thrust, a fossilized megasplay fault within the Shimanto Accretionary Complex, Japan, suggest dynamic sudden change in redox state associated with seismic faulting and fluid flow. Fluids migrating along the fault zone were relatively oxidized during the pre-failure fluid pressurization stage of the seismic cycle, but were relatively reduced during the immediate post-failure stage. The generation of a reducing post-failure hydrothermal regime may be associated with seismogenic rupture along the megasplay fault, involving the advection of exotic reducing fluid from deeper levels or in situ generation of hydrogen by co-seismic mechanochemical reactions.