中国东部多金属硫化物矽卡岩矿床中的伴生金
来源期刊：中南大学学报(自然科学版)1990年第4期
论文作者：王大伟 张术根 吴承建
文章页码：339 - 351
关键词：矽卡岩； 矿床； 伴生矿物； 金
Key words：skarn； deposit； associated mineral； gold
摘 要：中国金矿资源44%是来自伴生金。而其中主要又是来自多金属硫化物矽卡岩型矿床。这类矿床主要分布在中国东部。尤其集中在长江中下游。这类矿床受中国东部中生代以后的构造岩浆活动控制。矿床主要分布在下杨子拗陷及郯庐断裂两侧及不同构造体系交汇部位。这里均发育燕山期的中酸性的小岩体或浅成斑岩体。多系花岗闪长岩及花岗闪长斑岩。金矿地层则主要是石炭纪、二迭纪及三迭纪的白云灰岩和灰岩。富金的矽卡岩矿体常产在侵入体的接触带及外接触带的破碎带。矿石的主要金属矿物为黄铜矿、黄铁矿、毒砂、磁铁矿、闪锌矿、方铅矿、铜蓝、雄黄、雌黄等。金和铜的相关性最明显,有的矿床相关系数为0.8～0.9。主要载金矿物为黄铜矿、黄铁矿、寿砂、斑铜矿、闪锌矿、雄黄、雌黄等。金常以自然金、金银矿、碲金矿等赋存于载体矿物中,粒度极小,为显微或次显微金,也还有少量晶格金。研究表明金主要形成在硫化物阶段,金是以硫金络离子形式迁移。碱性还原条件有利于金的迁移。而氧逸度的减小,温度降低,酸性增强,有利于硫金络离子分解沉淀。
Abstract: Associated gold accounts for approximately 44 percent of Chinese gold resources and principally ccurs inp olymetallic sulfide skarn deposits.These deposits are located in the eastern part of China,especially in the middle and lower reaches of the Yangtse River.Geologically,they are distributed in the Yangtse Deep and Tanlu Fault related with the magma-tectonic movement,and mainly occur in the contact zone or the external-contact broken zone of Yanshan neutral-acid igneous rock with late paleaozoic Era-Mesozoic Era carbonate formation.The average Au content of ores varies between 1～2g/t.The main carrying-Au minerals are chalcopyrite,pyrite,bornite,etc..The common Au-mineralsare gold,electrum,calaverite,etc.,occuring mainly in the form of submiero-gold,less of microvisible-gold and much less of lattice-gold.The Au-minerals precipitated at the sulfide stage of skarn mineralizing process.Gold is transported in the form of Au-S complexes.An alkalic and reducing condition is suitable for their transportation.Temperature drop,fO2 decrease and acidity inereare will contribute to their dissociation and precipitation.The changes of physico-chemical conditions and of complex agent′s concentration in ore forming solution are the direct cause for the precipitation of gold.
