东太平洋海隆海底热液蠕虫管道矿化特征及其成因  

Mineralization Characteristics and Genesis of Worm-Tubes from Seafloor Hydrothermal Fields at East Pacific Rise

作　　者：罗礼涛 王叶剑 蔡翌旸 董传奇 韩喜球 Luo Litao;Wang Yejian;Cai Yiyang;Dong Chuanqi;Han Xiqiu(Institute of Sedimentary Geology,Chengdu University of Technology,Chengdu 610059,China;Key Laboratory of Submarine Geosciences&Second Institute of Oceanography,Ministry of Natural Resources,Hangzhou 310012,China;School of Oceanography,Shanghai Jiao Tong University,Shanghai 200240,China)

机构地区：[1]成都理工大学沉积地质研究院,四川成都610059 [2]自然资源部海底科学重点实验室,自然资源部第二海洋研究所,浙江杭州310012 [3]上海交通大学海洋学院,上海200240

出　　处：《地球科学》2024年第1期224-237,共14页Earth Science

基　　金：国家重点研发计划项目课题(No.2021YFF0501304);国家自然科学基金面上项目(No.41976076)。

摘　　要：热液管状蠕虫生物矿化现象在海底热液喷口区发育广泛,但蠕虫管道矿化和风化氧化过程及其控制因素知之甚少.对采自东太平洋海隆热液蠕虫矿化管道样品开展了高分辨率矿物学和元素分布研究.结果表明,样品具有以胶状黄铁矿为主的多圈层矿化结构,分为快速(F型)和慢速矿化(S型)两种类型.相比“S型”样品,“F型”的管壁更厚,同心层的数量少、间隙小、厚度均一.这主要受矿物沉淀速率的影响,即矿物的快速沉淀加快了蠕虫管道生长和矿化.此外,“F型”样品外壁分布的草莓状黄铁矿,表明纳-微米晶硫化物矿物的定向生长是形成胶状黄铁矿带的重要中间途径.而“S型”管壁从内到外具有氧化程度逐渐增加、胶状黄铁矿逐渐减薄的显著特征,指示样品同时受到了后期低温、富Fe-Si热液流体和低温海水风化氧化作用的影响.本项研究为理解现代海底热液系统的管状蠕虫矿化机制提供了新见解.Hydrothermal tubeworms biomineralization is widely developed in seafloor hydrothermal field,but the processes of mineralization,weathering and oxidation,as well as the controlling factors are poorly understood.In this paper,we use a detailed mineralogy observation and elemental in situ analysis methods to study mineralized worm-tubes from hydrothermal fields on the East Pacific Rise.The results show that the samples have a multilayered mineralization structure dominated by colloform pyrite and are classified into two types of fast(F-type)and slow mineralization(S-type).Compared with the"S-type",the"F-type"has thicker tube walls,fewer concentric layers,smaller gaps,and uniform thickness.This is mainly influenced by the rate of mineral precipitation,i.e.,the rapid precipitation of minerals accelerates worm tube growth and mineralization.In addition,the distribution of framboidal pyrite on the outer layers of"F-type"worm-tube wall suggests that the directional growth of nano-micron crystalline sulfide minerals is an important intermediate pathway for the formation of the colloform pyrite bands.The"S-type"is characterized by a gradual increase in oxidation and a gradual thinning of colloform pyrite bands from the inside to the outside,indicating that the sample was both affected by the oxidation of late low-temperature,Fe-Si-rich hydrothermal fluids and low-temperature seawater weathering.This study provides a new insight into understanding the mineralization mechanism of worm-tubes from modern seafloor hydrothermal systems.

关 键 词：海底热液 管状蠕虫 矿物学 管道圈层结构 硫化物矿化 风化氧化 

分 类 号：P736.3[天文地球—海洋地质]