Water-rock interaction observed in the brittle-plastic transition zone
Water-rock interaction observed in the brittle-plastic transition zone
复制标题
脆塑过渡带中观察到的水岩相互作用
DOI：
10.1186/bf03353313
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发表时间：
2002
期刊：
影响因子：
--
通讯作者：
Y. Kobayashi
中科院分区：
文献类型：
--
作者：
K. Fujimoto;T. Ohtani;N. Shigematsu;Y. Miyashita;Tomoaki Tomita;Hidemi Tanaka;K. Omura;Y. Kobayashi
通过岩石蚀变和断裂岩石地球化学研究，推断了与古断裂活动有关的流体相特征。日本东北部的波多川断裂带是一条以白垩纪花岗岩类为主的脆性和塑性变形断层岩紧密组合为特征的折返孕震带。绿帘石和绿帘石是两种岩石中的主要蚀变矿物。然而，方解石仅在下白垩统部分发育。即使在弱变形的花岗闪长岩中，氧同位素比值的降低和绿帘石、绿帘石的存在也是水-岩相互作用的证据。水/岩比被解释为相对较小，流体化学被糜棱岩中的寄主岩石化学缓冲。方解石在脆性结构的发生解释了在剪切带演化过程中的水化学变化。在碎裂变形过程中可能引入了富CO2流体，CO2浓度的增加导致方解石的沉淀。
Rock alteration and geochemistry of the fault rocks are examined to infer the characteristics of the fluid phase related to the ancient fault activity. The Hatagawa Fault Zone, northeast Japan, is an exhumed seismogenic zone which is characterized by close association of brittlely and plastically deformed fault rocks mostly derived from Cretaceous granitoids. Epidote and chlorite are dominant alteration minerals in both rocks. However, calcite is characteristically developed in the cataclastic part only. Decrease in oxygen isotope ratio and existence of epidote and chlorite, even in weakly deformed granodiorite, is evidence of water-rock interaction. The water/rock ratio is interpreted to be relatively small and fluid chemistry is buffered by host rock chemistry in the mylonite. The occurrence of calcite in brittle structures is explained by changes in water chemistry during shear zone evolution. CO2-rich fluid was probably introduced during cataclastic deformation and increased CO2 concentration resulted in precipitation of calcite.
影响因子：
4.4
作者：
JOHNSON, JW;OELKERS, EH;HELGESON, HC
通讯作者：
HELGESON, HC