Institute of Gold Geology

Peoples, China

Institute of Gold Geology

Peoples, China
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Wang K.,Jilin University | Min Q.,Institute of Gold Geology | Zhang X.,Jilin University | Wan D.,Jilin University | Xiao L.,Institute of Gold Geology
Acta Petrologica Sinica | Year: 2011

Jinchang gold deposit is a superlarge one with three different kinds of mineralization, which are cryptoexplosive breccia pipe type, bedded micro-fine vein disseminated type as well as fault-controlled quartz-vein and altered rock type respectively. This paper carried out a comparative study on fluid inclusions occurred in quartz of the three-type ores from petrography, microthermometry, compositional and hydrogen-oxygen isotope analyses as well as SEM/EDS analysis of daughter minerals etc. aspects, the results show that the ore-forming fluids of the three-type mineralization posed different geochemical features. The ore-forming fluids of the cryptoexplosive pipe type mineralization belong to magmatic-hydrothermal transitional fluids: that of the micro-fine vein disseminated type mineralization belong to highly saline solutions with a complex composition: whereas the ore-forming fluids of the fault-controlled quartz-vein and altered rock type mineralization belong to highly saline NaCl-H2O solutions. The composition of hydrogen-oxygen isotopes of fluid inclusions reveal that they all came from magmatic activities. Combined with the occurrences of ore bodies and geochronological data existed, the conclusion was made that the metallogenic evolution sequence in the mining district is cryptoexplosive breccia pipe type→ bedded micro-fine vein disseminated type→ fault-controlled quartz-vein and altered rock type and Jinchang gold deposit is the result of superimposition of mimeralization of magmatic fluids at different phases.

Wang K.,Jilin University | Qing M.,Institute of Gold Geology | Sun F.,Jilin University | Wan D.,Jilin University | And 3 more authors.
Acta Petrologica Sinica | Year: 2010

Xiaoxinaneha gold-copper deposit occurred in granodiorite-quartz diorite intrusions of Hercynian epoch. The mineralization of it mainly composed of large quartz vein type and fine quartz veinlet type, with molybdenite-quartz veins superimposed only locally. Fluid inclusion study shows that quartz in both of gold-copper ore veins and in molybdenite-quartz veins contain the same kinds of fluid inclusions, which include NaCl daughter mineral-bearing, gaseous and gas-rich as well as aqueous two-phase fluid inclusions. The similarity of homogenization temperature and salinity of the same kind of fluid inclusions reveals that the geochemical nature of ore-forming solutions of gold-copper and molybdenum mineralization have much in common. Hydrogen-oxygen isotopes of fluid inclusions imply they both came from magmatic fluids. Re-Os isotopic dating of molybdenite shows that molybdenum mineralization happened in ca. 109Ma, whereas 40Ar- 39 Ar isotopic dating of quartz in gold-copper veins reveals that gold-copper mineralization happened in 123. 35 ± 0. 8Ma. Combined with the results of chronological study of magmatic intrusions in the mining area, the conclusion were made that the origin of gold-copper mineralization mainly related with fine grained granodiorite intrusion of late phase of Yanshan, while the origin of molybdenum mineralization mainly related with granite porphyry of late phase of Yanshan, which successively emplaced after fine grained granodiorite intrusion in the mining area.

Wang K.-Y.,Jilin University | Qing M.,Institute of Gold Geology | Bian H.-Y.,Chinese People's Armed Police forces Academy | Wan D.,Jilin University | And 3 more authors.
Jilin Daxue Xuebao (Diqiu Kexue Ban)/Journal of Jilin University (Earth Science Edition) | Year: 2010

The systematic petrographic, microthermometric as well as laser Raman microspectroscopic studies on fluid inclusions developed in auriferous quartz veins collected from Wulong gold deposit were carried out. The results show that there exist three types of primary fluid inclusions in vein quartz minerals, CO 2 ± CH 4, H 2O-CO 2 ± CH 4 and aqueous two-phase respectively. The microthermometric research of different kinds of fluid inclusions reveals that the homogenization temperatures of H 2O-CO 2 ± CH 4 type fluid inclusions range from 287.8°C to 382.5°C, the salinities are between 0.42%-4.87%NaCl. The homogenization temperatures of two-phase aqueous fluid inclusions vary from 198.5°C to 338.4°C, and the salinities between 2.24%-6.88%NaCl. Thecomposition of gaseous phases in there types of fluid inclusions are dominated by CO 2 and CH 4, with largely variable relative content. Bycomprehensive studies, the conclusion can be drawn that the ore-forming fluid of auriferous quartz veins in Wulong gold deposit belongs to the medium temperature, low salinity and CO 2-bearing solutions. It was derived from magmatic activities and experienced reaction with country rocks during their transportation and accumulation processes, which resulted in the release of CH 4 into solutions and formation of mineralizing fluids enriched in CO 2 and CH 4.

Zhao Y.-S.,Institute of Gold Geology | Zhao Y.-S.,China University of Geosciences | Yan J.-P.,China University of Geosciences | Yang L.-Q.,Institute of Gold Geology | And 2 more authors.
Kuangwu Yanshi/ Journal of Mineralogy and Petrology | Year: 2013

A suite of intermediate-acidic volcanic tuff occurs in the east and outskirt of Jinchang Cu-Au deposit. It has variable w(SiO2) (66. 32%∼75. 56%), w(Al2O3)(12. 09%∼15. 64%) contents and higher CaO and Na2O contents than MgO and K2O,with w(K2O+Na2O) varying from 6.40% to 7. 91% and Al 2O3/(CaO+K2O+Na2O)

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