广东长坑金银矿床矿石类型及矿物组合

长坑金银矿床中金和银分别构成独立的金矿体和银矿体.矿床的主要矿石类型包括原生矿石和次生氧化矿石.氧化矿石的矿物种类简单,主要是石英,其次是粘土矿物,少量的针铁矿、臭葱石,微量的磁铁矿、锆石、黄铁矿和其他硫化物,偶见自然金.原生金矿石包括硅质金矿石、钙硅质金矿石、铝硅质金矿石三种类型,原生银矿石主要是硅质银矿石.原生金矿矿石矿物包括黄铁矿、雄黄、雌黄、重晶石、辉锑矿,其次是白铁矿和极少量毒砂和自然金,为一套浅成低温矿物组合.原生银矿矿石矿物是方铅矿、闪锌矿、银黝铜矿、深红银矿、硫锑铜银矿、硫锑铅银矿、辉锑银矿、辉银矿,次要矿物有黄铁矿、黝铜矿、黄铜矿、脆硫锑银矿、淡红银矿,是一套中深成中温的含银单硫化物和含银硫盐矿物组合.反映金、银矿床分属浅成低温和中深成中温热液交代成因的两次不同成矿作用的产物,金矿成矿在先,银矿成矿在后并叠加改造了金矿.

Ore types and mineral assemblage of the Changkeng Au-Ag deposit, Guangdong, South China

The gold-silver ore-bodies are hosted by sedimentary rocks and occur independently in one brecciated structure zone between Upper Carboniferous and Lower Triassic which is characterized with upper gold and lower silver in the Changkeng gold-silver deposit of Guangdong Province,South China.The main ore types have oxidation ore-body and original ore-body.The minerals in the oxidation ore-body simply comprise quartz and clays dominantly,and a few limolite plus scorodite,and minor magnetite,zircon,pyrite and other sulfides plus native gold observed occasionally.The original ore types of gold mainly include siliceous gold-bearing rock,calcareous siliceous gold-bearing rock and aluminium siliceous gold-bearing rock.But the original ore type of silver is only siliceous silver-bearing rock.The mineral assemblage of original gold-bearing rock is low temperature minerals of hypergene,which consists of pyrite,realgar,orpiment,barite,antimonite,and a few marcasite, fluorite,minor arsenopyrite.The minerals of original silver-bearing rock are mediate temperature mineral assemblage of mesogene,which consists of galena,sphalerite,freibergite,pyrargyrite,polybasite,andorite, miargyrite,argentite,and a few pyrite,tetrahedrite,chalcopyrite,owyheeite and proustite.The characteristics all above mentioned of the ore-bodies and their mineral assemblage could be the evidences to conclude that the gold deposit and silver deposit are formed by hydrothermal replacement mineralization under the condition of hypergene with low temperature and mesogene with mediate temperature respectively.The gold deposit occurred earlier,and silver formed later and altered the gold deposit.