冲绳海槽热液成矿机理特征剖析及资源潜力预测

Analysis of hydrothermal mineralization characteristics and prediction of resource potential in the Okinawa Trough

  • 摘要: 本研究聚焦冲绳海槽这一当前处于初始扩张阶段的弧后盆地,系统剖析其热液成矿机理特征并评估资源潜力。冲绳海槽作为西太平洋极具经济潜力的海底热液矿区,已发现近20个热液成矿区,成矿类型丰富且Au和Ag等贵金属含量高,是日本黑矿型火山成因块状硫化物(volcanogenic massive sulfide,VMS)的现代类似物。本研究运用地球系统科学的思想,从多维度展开分析,发现冲绳海槽弧后盆地成矿系统呈现 “构造-流体-沉积物-微生物” 多要素耦合特征,突破了传统的单一因素控矿的认知。构造上,受弧后裂谷与俯冲脊叠加作用,形成幕式构造活动控制下的成矿活跃区;流体来源具 “双重性”,岩浆流体与海水循环协同贡献,相分离作用调控流体性质与金属迁移;流体-沉积物相互作用改变流体化学性质,为成矿提供有利条件;微生物在成矿初始与后期蚀变中发挥关键作用。同时,当前在冲绳海槽已初步实现了对现代黑矿型VMS矿床钻探调查和形成过程的现场观测,其矿物组合、蚀变分带和成矿环境与古代黑矿高度相似,为研究这种类型的矿床成矿规律提供了宝贵的契机。本文也通过对已有调查成果的综合剖析,系统建立了古今VMS矿床的成矿关联。资源潜力初步预测显示,该区域矿床规模可观、类型多样,贵金属与贱金属协同富集,且明确了俯冲脊延伸带、深部隐伏矿体勘探及流体监测和原位种植等未来勘探方向。希望通过本文的努力完善弧后盆地热液成矿理论,并为未来西太平洋的资源勘探提供参考。

     

    Abstract: This study focuses on the Okinawa Trough, a typical back-arc basin currently in the initial rifting and expansion stage, to systematically analyze the characteristics of its hydrothermal mineralization mechanism and evaluate its resource potential. As a promising western Pacific submarine hydrothermal mining area, it has ~20 discovered hydrothermal mineralization zones and serves as a modern analog for Japan’s Kuroko-type volcanogenic massive sulfide (VMS) deposits. Using Earth system science, the study analyzes tectonics, magmatism, fluids, sedimentation, and microorganisms, revealing the trough’s “tectonics-fluids-sediments-microorganisms” multi-factor coupling mineralization, subverting the traditional view of mineralization controlled by a single factor. Tectonically, back-arc rifts and subduction ridges form mineralization zones via episodic activity. Fluids have dual sources (magmatic/seawater) with phase separation regulating properties and metal migration. Fluids-sediments interaction alters fluid chemistry for mineralization. Microorganisms matter in early mineralization and late alteration. The trough also enables initial on-site observation of modern Kuroko-type VMS formation, with its mineral assemblages, alteration zoning, and environment resembling ancient deposits—ideal for studying mineralization rules. Preliminary prediction shows large deposit scale, diverse types, and synergistic precious/base metal enrichment. Future exploration directions include subduction ridge extensions, deep concealed orebodies, fluid monitoring, and in-situ cultivation. This study advances back-arc basin hydrothermal mineralization theory and guides western Pacific resource exploration.

     

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