| WANG Shujie,LI Huaiming,ZHAI Shikui,YU Zenghui,SHAO Zongze,CAI Zongwei. 2017. Mineralogical characteristics of polymetallic sulfides from the Deyin-1 hydrothermal field near 15°S, southern Mid-Atlantic Ridge. Acta Oceanologica Sinica, 36(2):22－34 |
| Mineralogical characteristics of polymetallic sulfides from the Deyin-1 hydrothermal field near 15°S, southern Mid-Atlantic Ridge |
| 南大西洋中脊15°S附近德音1号热液区多金属硫化物的矿物学特征 |
| Received:April 20, 2016 Revised:June 15, 2016 |
| DOI：10.1007/s13131-016-0961-3 |
| Key words:mineralogical characteristics mineral-forming sequence polymetallic sulfides Deyin-1 hydrothermal field southern Mid-Atlantic Ridge |
| 中文关键词: 矿物学特征 矿物结晶顺序 多金属硫化物 德音1号热液区 南大西洋中脊 |
| 基金项目:The National Basic Research Program (973 Program) of China under contract No. 2013CB429702; the National Oceanic Major Project of 12th Five Year under contract No. DY125-11-R-05. |
| Author Name | Affiliation | E-mail | | WANG Shujie | Key Laboratory of Submarine Geosciences and Prospecting Techniques of Ministry of Education, College of Marine Geosciences, Ocean University of China, Qingdao 266100, China | | | LI Huaiming | Key Laboratory of Submarine Geosciences, Second Institute of Oceanography, State Oceanic Administration, Hangzhou 310012, China | | | ZHAI Shikui | Key Laboratory of Submarine Geosciences and Prospecting Techniques of Ministry of Education, College of Marine Geosciences, Ocean University of China, Qingdao 266100, China | zhai2000@ouc.edu.cn | | YU Zenghui | Key Laboratory of Submarine Geosciences and Prospecting Techniques of Ministry of Education, College of Marine Geosciences, Ocean University of China, Qingdao 266100, China | | | SHAO Zongze | Key Laboratory of Marine Biogenetic Resources, Third Institute of Oceanography, State Oceanic Administration, Xiamen 361005, China | | | CAI Zongwei | Key Laboratory of Submarine Geosciences and Prospecting Techniques of Ministry of Education, College of Marine Geosciences, Ocean University of China, Qingdao 266100, China | |
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| Abstract: |
| A seafloor hydrothermal field, named Deyin-1 later, near 15°S southern Mid-Atlantic Ridge (SMAR) was newly found during the 22nd cruise carried out by the China Ocean Mineral Resources Research & Development Association (COMRA). Sulfide samples were collected at three stations from the hydrothermal field during the 26th cruise in 2012. In this paper, mineralogical characteristics of the sulfides were analyzed with optical microscope, X-ray diffractometer, scanning electron microscope and electron microprobe to study the crystallization sequence of minerals and the process of hydrothermal mineralization. According to the difference of the ore-forming metal elements, the sulfide samples can be divided into three types:(1) the Fe-rich sulfide, which contains mainly pyrite and chalcopyrite; (2) the Fe-Cu-rich sulfide consisting predominantly of pyrite, chalcopyrite and isocubanite, with lesser amount of sphalerite, marmatite and pyrrhotine; and (3) the Fe-Zn-rich sulfide dominated by pyrite, sphalerite and marmatite, with variable amounts of chalcopyrite, isocubanite, pyrrhotine, marcasite, galena and gratonite. Mineral precipitations in these sulfides are in the sequence of chalcopyrite (isocubanite and possible coarse pyrite), fine pyrite, sphalerite (marmatite), galena, gratonite and then the minerals out of the dissolution. Two morphologically distinct generations (Py-I and Py-II) of pyrite are identified in each of the samples; inclusions of marmatite tend to exist in the coarse pyrite crystals (Py-I). Sphalerite in the Fe-Zn-rich sulfide is characterized by a "chalcopyrite disease" phenomenon. Mineral paragenetic relationships and a wide range of chemical compositions suggest that the environment of hydrothermal mineralization was largely changing. By comparison, the Fe-rich sulfide was formed in a relatively stable environment with a high temperature, but the conditions for the formation of the Fe-Cu-rich sulfide were variable. The Fe-Zn-rich sulfide was precipitated during the hydrothermal venting at relatively low temperature. |
| 中文摘要: |
| 中国大洋协会“22航次”在南大西洋中脊15°S附近发现了一个新的热液活动区，即德音1号热液区。2012年，“大洋26航次”在该热液区采集到了3个站位的硫化物样品。本文对采集到的样品分别进行了镜下观察、X射线衍射（XRD）、扫描电镜及电子探针分析等，系统地研究了热液硫化物的矿物学特征，初步探讨了矿物的结晶顺序及热液成矿作用过程。研究结果表明：南大西洋中脊15°S附近热液活动区硫化物可分为三种类型-富Fe型硫化物、富Fe-Cu型硫化物和富Fe-Zn型硫化物。其中，富Fe型硫化物以黄铁矿和黄铜矿为主；富Fe-Cu型硫化物矿物组成主要为黄铁矿、黄铜矿和方铁黄铜矿，可见少量的（铁）闪锌矿和磁黄铁矿；富Fe-Zn型硫化物组成矿物种类较多，以黄铁矿和（铁）闪锌矿为主，可见少量黄铜矿、方铁黄铜矿、磁黄铁矿、白铁矿、方铅矿和细硫砷铅矿等。热液硫化物中矿物的结晶顺序为：黄铜矿（方铁黄铜矿和可能的粗粒黄铁矿）、细粒黄铁矿、闪锌矿（铁闪锌矿）、方铅矿和细硫砷铅矿以及出溶矿物。在所有硫化物样品中普遍存在两个世代的黄铁矿，第一世代黄铁矿普遍患有“（铁）闪锌矿病”，富Fe-Zn型硫化物中的闪锌矿患有“黄铜矿病”。矿物的共生组合关系和矿物化学成分较大的变化区间都说明热液成矿作用的环境条件（主要是温度和成矿介质的化学组成等）变化剧烈（较大）且有反复性变化。相比之下，富Fe型硫化物形成于相对稳定环境中，成矿温度高；富Fe-Cu型硫化物的成矿环境条件变化较大；目前正在活动的热液喷口富Fe-Zn型硫化物的成矿温度相对较低。 |
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