冲绳海槽海底冷泉-热液系统相互作用

Interaction between seafloor cold seeps and adjacent hydrothermal activities in the Okinawa Trough

热液和冷泉活动是现代深海环境中两个重要的极端系统,它们均是岩石圈与外部圈层之间进行物质、能量转移和交换的重要途径,它们之间既有显著差异,但也存在很多相似点。一系列调查研究表明,在某些特殊构造单元,热液和冷泉活动可能并不是彼此孤立的,而是在构造地质、生物生态和元素循环上存在某种相互作用或耦合关系。冲绳海槽作为西太平洋一个典型的弧后盆地,发育了繁盛的热液和冷泉活动,是研究这两个海底极端系统相互影响机制的天然实验室。在大量文献调研和野外精细探测结果的基础上,分析了冲绳海槽内相互毗邻的冷泉和热液之间的物质扩散过程及生物地球化学作用,初步建立了两个极端系统内两种不同流体相互作用的概念模型,认识到未来如对两个深海极端环境共生区构造发育特征、地层流体演化、生物群落以及矿物元素组成进行系统分析,将有助于建立更加完善的冷泉-热液两个系统在物质和能量上的耦合关系模型,同时也有助于揭示它们在生物生态之间的沟通融合规律,最终可建立盆地尺度上热液-冷泉区相互作用模式,从而加深对西太平洋甚至全球范围内冷泉-热液两个极端环境系统甚至“流体-固体”耦合的规律性认识。

As the seafloor extreme environmental systems,both hydrothermal vents and cold seeps are the critical pathways between the lithosphere and exosphere (biosphere,hydrosphere and atmosphere) for transfer and exchange of materials and energies.There are significant differences,but also many similarities between the two systems.Recent investigations show that in some special tectonic units,hydrothermal vents and cold seeps are not isolated from each other,but instead there are some interactions or coupling relationships in terms of tectonic geology,biological ecology and element cyclicity.As a typical back-arc basin in the western Pacific Ocean,there are abundant hydrothermal vents and cold seeps developed in the Okinawa Trough (OT).Therefore,it has become an ideal natural laboratory for studying the two extreme environmental systems and their interactions.On the basis of literature researches and careful field case studies,we investigate the material diffusion process and biogeochemical process between cold seeps and hydrothermal vents adjacent to each other within the trough.A conceptual model is then established for the interactions between the fluids from the two extreme systems.Our results suggest that it would help to establish a more complete model of the coupling relationship between the two systems in the future,if the structural development characteristics,pore fluid evolution,biological communities,and mineral chemistry of the two deep-sea extreme environments are systematically analyzed. Moreover,it will help to reveal the interaction between them in biological ecology and finally establish a model of interaction between hydrothermal vents and cold seeps on the basin scale,so as to better understand the interaction process between cold seeps and hydrothermal systems and even the coupling of “flow-solid” in the Western Pacific Ocean or the whole Earth.