Sulfide mineralization in an ultramafic-rock hosted seafloor hydrothermal system: From serpentinization to the formation of Cu-Zn-(Co)-rich massive sulfides
Sulfide mineralization in an ultramafic-rock hosted seafloor hydrothermal system: From serpentinization to the formation of Cu-Zn-(Co)-rich massive sulfides
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DOI：
10.1016/j.margeo.2007.05.007
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发表时间：
2007-11
期刊：
影响因子：
2.9
通讯作者：
Ana Filipa A. Marques;Fernando J.A.S. Barriga;Steven D. Scott
中科院分区：
文献类型：
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作者：
Ana Filipa A. Marques;Fernando J.A.S. Barriga;Steven D. Scott
彩虹喷口区是一个位于大西洋中脊的超镁质岩石海底热液系统，它释放出高温、酸性、富含金属的流体。热液产物包括富Cu-Zn - (Co)块状硫化物，其特征与基性火山型块状硫化物矿床相似。彩虹喷口区非矿化和矿化岩石的岩石学、矿物学和地球化学特征表明，蛇纹岩化橄榄岩为热液喷口系统的主体，但蛇纹岩化反应发生在硫化物成矿事件之前，且独立于硫化物成矿事件。硫化物矿化的开始反映在蛇纹石群矿物中广泛的结构和化学转变，显示出明显的热液腐蚀迹象。元素再活化在彩虹喷口区岩石中是一个反复出现的过程，在简单的橄榄岩蛇纹石化过程中，存在于橄榄石和辉石中的Ni和Cr分别被合并到伪晶蛇纹石网和玄武岩中。后来，由于广泛的热液蚀变，镍从假晶蛇纹石中重新活化到新形成的硫化物中。整体岩石地球化学和相关系数区分了不同的过程：蛇纹石化、硫化物矿化和与海水循环有关的浅层海底低温过程（如碳化、硫化物氧化和B和U吸收）。
The Rainbow vent field is an ultramafic rock-hosted seafloor hydrothermal system located on the Mid-Atlantic ridge issuing high temperature, acidic, metal-rich fluids. Hydrothermal products include Cu–Zn–(Co)-rich massive sulfides with characteristics comparable to those found in mafic volcanic-hosted massive sulfide deposits. Petrography, mineralogy and geochemistry of nonmineralized and mineralized rocks sampled in the Rainbow vent field indicate that serpentinized peridotites host the hydrothermal vent system but serpentinization reactions occurred prior to and independently of the sulfide mineralization event. The onset of sulfide mineralization is reflected by extensive textural and chemical transformations in the serpentine-group minerals that show clear signs of hydrothermal corrosion. Element remobilization is a recurrent process in the Rainbow vent field rocks and, during simple peridotite serpentinization, Ni and Cr present in olivine and pyroxene are incorporated in the pseudomorphic serpentine mesh and bastite, respectively. Ni is later remobilized from pseudomorphic serpentine into the newly formed sulfides as a result of extensive hydrothermal alteration. Bulk-rock geochemistry and correlation coefficients discriminate the different processes: serpentinization, sulfide mineralization and superficial seafloor low-temperature processes related to the circulation of seawater (e.g. carbonatization, sulfide oxidation and B and U uptake).