Coupled Fe–S isotope composition of sulfide chimneys dominated by temperature heterogeneity in seafloor hydrothermal systems  

海底热液系统中硫化物烟囱体的硫同位素和铁同位素

作　　者：Shujie Wang Weidong Sun Jing Huang Shikui Zhai Huaiming Li 王淑杰;孙卫东;黄晶;翟世奎;李怀明(Center of Deep Sea Research,Institute of Oceanology,Chinese Academy of Sciences,Qingdao 266071,China;Laboratory for Marine Mineral Resources,Pilot National Laboratory for Marine Science and Technology(Qingdao),Qingdao 266237,China;Center for Ocean Mega-Science,Chinese Academy of Sciences,Qingdao 266071,China;University of Chinese Academy of Sciences,Beijing 100049,China;Key Lab of Submarine Geosciences and Prospecting Techniques,Ministry of Education,College of Marine Geosciences,Ocean University of China,Qingdao 26610O,China;Key Laboratory of Submarine Geosciences,Second Institute of Oceanography,Ministry of Natural Resources,Hangzhou 310012,China)

机构地区：[1]Center of Deep Sea Research,Institute of Oceanology,Chinese Academy of Sciences,Qingdao 266071,China [2]Laboratory for Marine Mineral Resources,Pilot National Laboratory for Marine Science and Technology(Qingdao),Qingdao 266237,China [3]Center for Ocean Mega-Science,Chinese Academy of Sciences,Qingdao 266071,China [4]University of Chinese Academy of Sciences,Beijing 100049,China [5]Key Lab of Submarine Geosciences and Prospecting Techniques,Ministry of Education,College of Marine Geosciences,Ocean University of China,Qingdao 26610O,China [6]Key Laboratory of Submarine Geosciences,Second Institute of Oceanography,Ministry of Natural Resources,Hangzhou 310012,China

出　　处：《Science Bulletin》2020年第20期1767-1774,M0004,共9页科学通报（英文版）

基　　金：supported by the Strategic Priority Research Program (B) of Chinese Academy of Sciences (XDB42000000);the National Natural Science Foundation of China (41806061);the National Key Research & Development Program of China (2016YFC0600408);the Strategic Priority Research Program (A) of the Chinese Academy of Sciences (XDA22050103);the Taishan Scholar Program of Shandong (ts201712075);the AoShan Talents Cultivation Program supported by Qingdao Pilot National Laboratory for Marine Science and Technology (2017ASTCPOS07)。

摘　　要：Seafloor hydrothermal chimneys are significant metal resources and have fundamental effects on marine chemistry balance.Previous studies on growth of the chimneys focused on mineral composition and elemental distribution in chimney walls,but the isotopic composition of different elements and their correlations remain poorly understood.Here,we report lateral Fe and S isotopes from sulfides across a chimney wall in detail from the Deyin-1 hydrothermal field(DHF) on the South Mid-Atlantic Ridge.Pyrite was characterized by increases in both δ34S and δ56Fe from the exterior to the interior within the chimney wall,which is likely related to enhanced S and Fe isotope fractionation between pyrite and fluids derived from the temperature gradient.Furthermore,δ56Fe displayed a well-defined,linear,positive correlation with δ34S in pyrite from the DHF as well as in pyrite from other areas.A model of hydrothermal pyrite formation suggests that,under conditions with uniform hydrothermal fluid,different temperatures and similar pyrite-fluid exchange degrees could result in the observed linear relationships between δ34S and δ56Fe.The regular and coupled Fe-S isotope variations within the chimney wall efficiently constrain the process of hydrothermal sulfide formation.现代海底热液系统因其资源和环境价值而受到全球的广泛关注.然而,对热液烟囱体中不同元素的同位素组成、分布及其相互关系的认识还比较有限.本文详细研究了大西洋中脊15°S德音1号热液区中一个典型同心环结构的硫化物烟囱,发现:(1)黄铁矿的δ34S和δ56Fe值在烟囱壁上从外到内呈规律性增大;(2)黄铁矿的δ56Fe与δ34S之间呈明显的线性正相关关系,此特征在其他热液区也有发现.文章认为温度差异很大程度上影响了烟囱壁内铁同位素和硫同位素的变化.在热液保持稳定的条件下,硫化物沉淀过程中相似的矿物-流体交换程度可导致黄铁矿δ34S与δ56Fe之间的线性关系.这些规律对热液硫化物的形成过程,包括硫化物的沉淀和再结晶过程,提供了更为具体的约束条件.

关 键 词：Sulfide chimney Iron isotope Sulfur isotope TEMPERATURE 

分 类 号：P736.3[天文地球—海洋地质]