当前位置：
X-MOL 学术
›
Ore Geol. Rev.
›
论文详情
Our official English website, www.x-mol.net, welcomes your feedback! (Note: you will need to create a separate account there.)
Gold-telluride-sulfide association in the Jinqu Au deposit, Xiaoqinling region, central China: Implications for ore-forming conditions and processes
Ore Geology Reviews ( IF 3.3 ) Pub Date : 2020-10-01 , DOI: 10.1016/j.oregeorev.2020.103687 Ming Chang , Jiajun Liu , Emmanuel John M. Carranza , Chao Yin , Degao Zhai , Tong Wu , Dazhao Wang
Ore Geology Reviews ( IF 3.3 ) Pub Date : 2020-10-01 , DOI: 10.1016/j.oregeorev.2020.103687 Ming Chang , Jiajun Liu , Emmanuel John M. Carranza , Chao Yin , Degao Zhai , Tong Wu , Dazhao Wang
|
Abstract The Jinqu Au deposit, located in central Xiaoqinling gold field along the North China Craton’s southern margin, has total reserve of 21 t of Au with 4.23 g/t Au on average. It consists cccmainly of ore-bearing auriferous quartz veins in amphibolite facies metamorphic rocks of the Archean Taihua Group. The deposit’s mineral paragenesis and ore-forming processes have never been studied. This paper reports its mineral paragenesis, which includes sulfides (pyrite, galena, chalcopyrite, pyrrhotite, sphalerite, molybdenite and bornite), oxides (rutile, scheelite, hematite, magnetite), tellurides (sylvanite [(Au, Ag)2Te4], hessite [Ag2Te], petzite [Ag3AuTe2], krennerite [Au3AgTe8], calaverite [AuTe2], stutzite [Ag5−xTe3], empressite [AgTe], rucklidgeite [(Pb, Bi)3Te4], altaite [PbTe], volynskite [AgBiTe2], tetradymite [Bi2Te2S], lingbaoite (AgTe3) and melonite [NiTe2]) and native elements (tellurium and gold). Based on our data, the associated ore-forming processes can be deduced as: iron oxides → (CO2(g) and H2S(g) loss, ƒTe2/ƒS2 ratio increase) sulfides, Au-Ag-tellurides → (condensation of H2Te vapor) Pb-Bi-tellurides → (mixing with meteoric water) carbonate. It has been indicated by thermodynamic modelling that formation of Au-Ag-Te-bearing minerals occurred under physico-chemical conditions of logƒTe2 values from − 7.28 to − 3.21, logƒO2 values from − 26.67 to − 26.44, logƒH2S values from − 1.34 to 0.34, logƒS2 values from − 9.53 to − 5.64, logαAu+(aq)/αAg+(aq) values from − 4.72 to − 4.55 and pH values from 3.33 to 4.20 at 365℃ and logƒTe2 values from − 10.53 to − 6.62, logƒO2 values from − 31.99 to − 30.98, logƒH2S values from − 0.65 to − 0.36, logƒS2 values from − 13.62 to − 7.20, logαAu+(aq)/αAg+(aq) values from − 6.42 to − 6.21 at 335℃. The changes in physico-chemical conditions and in precipitation of Au-Ag-Te-bearing minerals were due to boiling or to condensation of Te-rich magmatic gas into ore-forming fluids. These reflect evolution from an early oxidizing to a later relatively reducing mineralization environment. Therefore, compared with the Dahu Au-Mo deposit and with the Yangzhaiyu Au deposit, which exist in the southern and northern parts of the Xiaoqinling region, respectively, the ore paragenesis and ore-forming physico-chemical conditions of the Jinqu Au deposit were different such that its characteristics are similar to low-sulfidation Au deposits.
更新日期：2020-10-01
京公网安备 11010802027423号