Geochemical Features of Sulfides from the Deyin-1 Hydrothermal Field at the Southern Mid-Atlantic Ridge near 15?S  

作　　者：WANG Shujie LI Huaiming ZHAI Shikui YU Zenghui CAI Zongwei 

机构地区：[1]Key Laboratory of Submarine Geosciences and Prospecting Techniques, Ministry of Education,College of Marine Geosciences, Ocean University of China, Qingdao 266100, P. R. China [2]Key Laboratory of Submarine Geosciences, Second Institute of Oceanography, State Oceanic Administration,Hangzhou 310012, P. R. China

出　　处：《Journal of Ocean University of China》2017年第6期1043-1054,共12页中国海洋大学学报（英文版）

基　　金：supported by the National Basic Research Program of China (No.2013CB429702);the National Oceanic Major Project of the China Ocean Mineral Resources Research and Development Association (No.DY125-11-R-05)

摘　　要：In this study, geochemical compositions of elements in sulfide samples collected from the Deyin-1 hydrothermal field near the 15?S southern Mid-Atlantic Ridge(SMAR) were analyzed by the X-ray fluorescence spectrometry(XRF) and inductively coupled plasma mass spectrometry(ICP-MS) to examine the enrichment regulations of ore-forming elements and hydrothermal mineralization. These sulfide precipitates can be classified macroscopically into three types: Fe-rich sulfide, Fe-Cu-rich sulfide and Fe-Zn-rich sulfide, and are characterized by the enrichment of base metal elements along with a sequence of Fe>Zn>Cu. Compared with sulfides from other hydrothermal fields on MAR, Zn concentrations of sulfides in the research area are significantly high, while Cu concentrations are relatively low. For all major, trace or rare-earth elements(REE), their concentrations and related characteristic parameters exhibit significant variations(up to one or two orders of magnitude), which indicates the sulfides from different hydrothermal vents or even a same station were formed at different stages of hydrothermal mineralization, and suggests the variations of chemical compositions of the hydrothermal fluid with respect to time. The hydrothermal temperatures of sulfides precipitation decreased gradually from station TVG10(st.TVG10) to st.TVG12, and to st.TVG11, indicating that the precipitation of hydrothermal sulfides is subjected to conditions changed from high temperature to low temperature, and that the hydrothermal activity of study area was at the late stage of a general trend of evolution from strong to weak. The abnormally low concentrations of REE in sulfides and their similar chondrite-normalized REE patterns show that REEs in all sulfides were derived from a same source, but underwent different processes of migration or enrichment, or sulfides were formed at different stages of hydrothermal mineralization. The sulfides collected from the active hydrothermal vent were mainly attributed to precipitating directly from the hydrotheIn this study, geochemical compositions of elements in sulfide samples collected from the Deyin-1 hydrothermal field near the 15°S southern Mid-Atlantic Ridge (SMAR) were analyzed by the X-ray fluorescence spectrometry (XRF) and inductively coupled plasma mass spectrometry (ICP-MS) to examine the enrichment regulations of ore-forming elements and hydrothermal mineralization. These sulfide precipitates can be classified macroscopically into three types: Fe-rich sulfide, Fe-Cu-rich sulfide and Fe-Zn-rich sulfide, and are characterized by the enrichment of base metal elements along with a sequence of Fe>Zn>Cu. Compared with sulfides from other hydrothermal fields on MAR, Zn concentrations of sulfides in the research area are significantly high, while Cu concentrations are relatively low. For all major, trace or rare-earth elements (REE), their concentrations and related characteristic parameters exhibit significant variations (up to one or two orders of magnitude), which indicates the sulfides from different hydrothermal vents or even a same station were formed at different stages of hydrothermal mineralization, and suggests the variations of chemical compositions of the hydrothermal fluid with respect to time. The hydrothermal temperatures of sulfides precipitation decreased gradually from station TVG10 (st.TVG10) to st.TVG12, and to st.TVG11, indicating that the precipitation of hydrothermal sulfides is subjected to conditions changed from high temperature to low temperature, and that the hydrothermal activity of study area was at the late stage of a general trend of evolution from strong to weak. The abnormally low concentrations of REE in sulfides and their similar chondrite-normalized REE patterns show that REEs in all sulfides were derived from a same source, but underwent different processes of migration or enrichment, or sulfides were formed at different stages of hydrothermal mineralization. The sulfides collected from the active hydrothermal vent were mainly attributed to precipitating directly from the h

关 键 词：southern MID-ATLANTIC RIDGE Deyin-1 HYDROTHERMAL field HYDROTHERMAL SULFIDE geochemistry of element MINERALIZATION 

分 类 号：P736.4[天文地球—海洋地质]