CAJ | 학술논문

通过电感耦合等离子体光谱仪（IC P-A ES ）以及扫描电镜等手段对超慢速扩张的西南印度洋中脊热液区的3个硫化物样品的金银含量及其赋存状态进行了研究。通过IC P-A ES测定金银含量，结果发现3个样品均有Au和Ag富集的现象。通过能谱-扫描电镜联用（SEM／EDS），在三个样品中发现了大量的金银矿物。其中S27-4中，主要以不规则粒状的银金矿和自然金的形式赋存于硫化物中或者晶粒之间，而S35-22中，则发现了大量的银矿物和部分银金矿。能谱分析表明银矿物中常伴随有一定量的卤族元素，推测以卤化银的形式存在，银金矿除了以粒间金赋存还可以呈乳滴状被吸附在黄铁矿表面或者晶棱上，推测与黄铁矿表面缺陷有关。S35-17样品中银金矿是唯一被发现的矿物相，以包体金、吸附金和间隙金形式赋存。由于不同样品中，银金矿的摩尔比有所不同，指示形成环境有所不同。研究结果表明，S27-4的成矿流体中，Ag主要以AgCl2－络合物迁移，Au经历了以AuCl2－络合物到AuHS0络合物为主的转变，指示了其温度从中高温到中低温的变化过程，说明了传导冷却在这个变化过程中有重要作用。S35-22中金银矿物的形成也具有类似的富集机制，但S35-22中卤化银的形成显示了早期高温高氯度的流体环境。而黑烟囱样品S35-17中银金矿的形成则与热液流体与海水的混合作用有密切关系。
통과전감우합등리자체광보의（IC P-A ES ）이급소묘전경등수단대초만속확장적서남인도양중척열액구적3개류화물양품적금은함량급기부존상태진행료연구。통과IC P-A ES측정금은함량，결과발현3개양품균유Au화Ag부집적현상。통과능보-소묘전경련용（SEM／EDS），재삼개양품중발현료대량적금은광물。기중S27-4중，주요이불규칙립상적은금광화자연금적형식부존우류화물중혹자정립지간，이S35-22중，칙발현료대량적은광물화부분은금광。능보분석표명은광물중상반수유일정량적서족원소，추측이서화은적형식존재，은금광제료이립간금부존환가이정유적상피흡부재황철광표면혹자정릉상，추측여황철광표면결함유관。S35-17양품중은금광시유일피발현적광물상，이포체금、흡부금화간극금형식부존。유우불동양품중，은금광적마이비유소불동，지시형성배경유소불동。연구결과표명，S27-4적성광류체중，Ag주요이AgCl2－락합물천이，Au경력료이AuCl2－락합물도AuHS0락합물위주적전변，지시료기온도종중고온도중저온적변화과정，설명료전도냉각재저개변화과정중유중요작용。S35-22중금은광물적형성야구유유사적부집궤제，단S35-22중서화은적형성현시료조기고온고록도적류체배경。이흑연창양품S35-17중은금광적형성칙여열액류체여해수적혼합작용유밀절관계。
In the present study ,content and occurrence of Au ,Ag in three submarine hydrothermal sulfide samples from the ul-tra-slow-spreading Southwest Indian Ridge (SWIR) were studied by using inductively coupled plasma-atomic emission spectrom-etry (ICP-AES) ,scanning electron microscopy (SEM ) and energy dispersive X-ray spectroscopy (EDS) .The results of ICP-AES show that all of the samples have signs of Au-Ag enrichment .By SEM/EDS ,we discovered a mass of gold-silver minerals in the samples .In S27-4 ,gold occurs as irregular-shaped native gold and electrum grains in sulfides or between crystal particles . However ,we discovered lots of Au-independent silver minerals except parts of electrum in S35-22 .EDS results of silver minerals indicate that silver minerals closely related with halogen element ,inferring that silver minerals may be silver halides .Electrum in S35-22 can be absorbed at the surface or crystal edge of pyrite besides occurring in or between sulfides as S 27-4 ,supposed to be related to surface defect in pyrite .Electrum is the only Au-Ag mineral discovered in S35-17 .These electrum gains occur as inclu-sion gold ,absorbed gold or fissure gold .In addition ,there are different Au-Ag mole ratios of electrum in three samples ,indica-ting distinct hydrothermal conditions .In the base of research before ,we consider that AgCl2- is the dominant complex of silver in ore-forming fluid of S27-4 ,however ,gold is transported as AuCl2- transforming to AuHS0 ,indicating that hydrothermal fluids decreased from high-moderate to moderate-low temperature and conductive cooling played an important role in this process .Simi-lar enrichment mechanism happened in S35-22 ,but silver halides discovered in S35-22 suggest a higher temperature and chloride in the early stage .However ,The enrichment of electrums in black smoke sample(S35-17) relates to mixing of hydrothermal flu-ids and seaw ater .