大洋中脊海底热液系统的演化特征及其成矿意义  

On the feature of seafloor hydrothermal systems' evolutionary and its mineralization in Mid-Ocean Ridge

作　　者：刘为勇[1] 郑连福[1] 陶春辉[1] 李怀明[1] 窦炳琚 

机构地区：[1]国家海洋局第二海洋研究所,国家海洋局海底科学重点实验室,浙江杭州310012

出　　处：《海洋学研究》2011年第1期25-33,共9页Journal of Marine Sciences

基　　金：中国大洋矿产资源研究开发协会资助项目(DY115-02-1-01);中国科学院海洋地质与环境重点实验室开放课题资助项目(MGE2009KG07)

摘　　要：大洋中脊海底热液系统的演化与成矿是复杂、综合的地质过程。归纳、分析了前人研究的资料认为,热源供给和热液活动构造体系是控制热液系统演化与成矿的关键因素。在快速扩张洋中脊热液系统中,岩浆的供给充裕,构造体系渗透性极好,演化时间较短,海底的热液循环输出过程可分为发生、持续和衰退3个阶段;在慢速扩张洋中脊热液系统中,岩浆的供给相对贫乏,但热源构造体系分布广泛,构造控制作用突出,持续演化可达几万年以上。在慢速及超慢速扩张洋中脊热液系统中,广泛、多类型的热源和优越的构造环境,可能更有利于热液流体的长期演化和富集成矿,因此未来有必要通过地质-地球物理和数学建模等多种勘探方法,深入研究其演化机理和成矿规律。Seafloor hydrothermal activity in Mid-Ocean Ridge has become one of hotspots in geosciences because of its valuable scientific researching significance.Hydrothermal systems at seafloor spreading centers are characterized by a complex interplay among magmatic,tectonic and biogeochemical processes linked by fluid circulation and heat transfer in the oceanic crust.It could be divided into three phases on the evolution of magma-controlled hydrothermal system,an initial phase,a living phase and a dying phase.The three phases simply reflects the evolution mechanism of hydrothermal system.On the basis of previous data collecting and studies,the authors consider that there are three corresponding hydrothermal activity phases at fast spreading centers,and they evolved with shorter phases,no more than ten years or decades.Although magmatic budget is not so robust at slow spreading centers,the characteristics of each phases are not obvious,and hydrothermal system with universal heat and special structure could continue more than ten thousand years or evolve with tens of thousand years episodically.So the authors affirm that hydrothermal processes are controlled by heat supply and tectonic conditions,such as Rainbow and TAG hydrothermal field in Mid Atlantic Ridge,or even Middle Valley hydrothermal field in Juan de Fuca Ridge,they all have experienced a long-term evolution caused by their sufficient heat supply and favorable superior tectonic conditions.Uncovered ultramafic rock and deeper extension brittle failure are common existent at ultra-slow spreading centers.It has been detected higher incidence of hydrothermal venting than calculated by Magmatic Budget Hypothesis in recent decades,such as Gakkel Ridge in the Arctic Ocean and Southwest Indian Ridge,certain segments areas with extra irregular heat supply and more favorable superior tectonic conditions may cause huge hydrothermal sulfide deposit by long-term cumulating.China have made great progress in prospecting seafloor hydrothermal activity at Southwest Indian Spre

关 键 词：大洋中脊 热液系统 演化特征 多金属硫化物 

分 类 号：P738[天文地球—海洋地质]