西秦岭寨上特大型金矿床碲化物与金矿物共生关系研究

Resesrch on the Paragenetic Relationship between Tellurium and Gold Minerals in Zhaishang Gold Deposit,West Qinling

在研究寨上金矿矿石矿物过程中,新鉴定出碲金银矿、板碲金银矿、碲汞矿及碲镍矿,重点研究了这几种碲化物以及与之共生的自然金的矿物学特征和微量元素变化特征。碲化物在矿床中表现为Ag3AuTe2(碲金银矿)-AuTe2(碲金矿)-Au(自然金)的共生组合,说明其形成于低温环境。自然金或者含银自然金在矿床中表现为Ag3AuTe2(碲金银矿)-Ag2Te(碲银矿)-Au(含银自然金)的共生组合,说明在低温环境下也可以形成自然金矿物。寨上金矿碲化物与自然金的生成顺序:含砷碲金银矿—碲金银矿—板碲金银矿—碲金矿—碲汞矿—银金矿—自然金。寨上金矿成矿机制是当成矿流体中的S元素消耗殆尽时,Te元素含量增高,开始形成银的碲化物,如碲银矿和碲金银矿等,由于流体中还残留有少量As元素,所以碲金银矿中含极少量的As。当流体中的Te元素消耗殆尽时,形成银金矿和自然金。寨上金矿具有形成超大型金矿的条件,属于与花岗岩有关的金矿床。

In the process of researching ore mineral in Zhaishang gold deposit,we discovery Petzite, Muthmannite, Coloradoite,Melonite,and emphasis study on the characteristics of mineralogy and trace element variation of tel- luride and native gold.Telluride performance the paragenesis of Ag3AuTe2 （petzite）-AuTe2 （calaverite）-Au（native gold） in the deposit,it shows that the telluride form at low temperature.native gold or include Ag native gold performance the paragenesis of Ag3AuTe2 （petzite）-Ag2Te （hessite）-Au （Ag,Au） in deposit.The generated sequence of telluride and native gold in Zhaishang gold deposit： As-petzite-petzite-muthmannite-ealsverite-coloradoite-elec- trum-native gold.The mineralization mechanism of Zhaishang deposit,when the S element of ore-forming fluids ex- haust,Te element content increase, and start form Ag-telluride,such as hessite and petzite,because there still re- main a small amount of As element in fluid,so the petzite contain small amount of As.While Te element in fluid deplete, form electrum and native gold.Zhaishang gold deposit have the conditions of foming large gold deposit,it belongs to the gold deposit related to granite.