西北印度洋天休热液区热液成因矿物特征与分布及其指示意义  

Characteristics,distribution and implication of hydrothermal minerals in Tianxiu Hydrothermal Field,Carlsberg Ridge,northwest Indian Ocean

作　　者：蔡翌旸 韩喜球 邱中炎 王叶剑 李谋 Samuel Olatunde Popoola CAI Yiyang;HAN Xiqiu;QIU Zhongyan;WANG Yejian;LI Mou;Samuel Olatunde Popoola(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;Ocean College,Zhejiang University,Zhoushan 316021,China)

机构地区：[1]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,杭州310012 [2]上海交通大学海洋学院,上海200240 [3]浙江大学海洋学院,舟山316021

出　　处：《海洋地质与第四纪地质》2020年第5期36-45,共10页Marine Geology & Quaternary Geology

基　　金：大洋“十三五”资源评价重大项目“多金属硫化物资源勘查—印度洋靶区项目”(DY135-S2-1-03);国家自然科学基金面上项目“卧蚕热液区热液沉积记录研究:对热液活动史及其驱动机制的指示”(41976075);“超镁铁岩型海底块状硫化物矿床中金的富集过程:以卡尔斯伯格脊天休热液区为例”(41976076);国家自然科学基金“水圈微生物”重大研究计划重点项目“海底热液区硫化物的微生物氧化作用:过程、机制及其对海洋硫循环的贡献”(91951201)。

摘　　要：海底沉积物中的热液成因矿物主要来自热液区热液产物堆积体的失稳垮塌搬运迁移和热液羽流自生矿物颗粒的沉降。热液成因矿物的类型和空间分布特征对于了解热液活动区的位置与范围具有重要的指示作用。天休热液区(3°41′N、63°50′E)位于卡尔斯伯格脊超镁铁岩系中,本文对采自该热液区及其周边的共4站表层沉积物样品进行研究,分析热液成因矿物的组成、丰度和粒度的空间变化情况。研究表明,在热液喷口近端(0~0.22 km)同时分布有垮塌迁移及热液羽流沉降来源的热液成因矿物,其中垮塌来源的矿物呈砾—粗砂级,以古巴矿等金属硫化物矿物及铁氧化物为主;羽流沉降来源的矿物呈砂—泥级,以Cu-Zn-Fe硫化物矿物(等轴古巴矿、古巴矿、闪锌矿和磁黄铁矿等)为主。在远喷口端(1.84~6.05 km)主要分布有羽流沉降来源的热液成因矿物,以砂—泥级的金属氧化物和氢氧化物为主。热液成因矿物的类型、粒度、丰度在空间上呈现出的规律性分布特征可以示踪未知的活动和非活动热液区的位置,并作为多金属硫化物资源的找矿标志。Hydrothermal minerals could originate from mass wasting of hydrothermal deposits or from the hydrothermal plume falling-out.The types and their spatial distribution of hydrothermal minerals are important indicators for constraining the location of hydrothermal field.The Tianxiu Hydrothermal Field(3°41′N,63°50′E)is an ultramafic-hosted field located on the Carlsberg Ridge,northwest Indian Ocean.In this paper,surface sediments collected from 4 stations near the active venting site of Tianxiu Hydrothermal Field and its surrounding regions were studied on hydrothermal minerals to understand their spatial variations on morphology,composition,abundance and particle size.Near the venting site(0~0.22 km)the hydrothermal minerals are dominated by Cu-Zn-Fe containing sulfide aggregates,in the size from gravel to sand,originated from the mass wasting of the sulfide deposits and precipitation from the hydrothermal fluid.For samples collected outside of the hydrothermal field(1.84~6.05 km away),the hydrothermal minerals are dominated by fine grain hydrothermal oxides and hydroxides derived from plume fallout.Our results suggest that the types and grain size of hydrothermal minerals and their spatial distribution can be served as a good indicator for tracking unknown active and inactive hydrothermal field and prospecting of the associated hydrothermal sulfide resources.

关 键 词：表层沉积物 热液成因矿物 天休热液区 卡尔斯伯格脊 印度洋 

分 类 号：P744[天文地球—海洋科学]