HE Cheng-zhong1,2, WANG Bin1, ZHAO Bo1, ZHANG De-hui1*, WANG Xin-yan1, HUANG Cheng1,3, YU Xiao1
1. School of Earth Science and Resources, China University of Geosciences(Beijing), Beijing 100083, China;
2. No.10 Gold Geological Party of CAPF, Kunming 650111, China;
3. No.9 Gold Geological Party of CAPF, Haikou 570100, China
Abstract: Summarizing that in the magmatic-hydrothermal system: The partition behaviors of Mo among minerals, melts, solution and vapour phases under different conditions and its influenced factors; Mo migrates mainly in the form of complex ion with valence of +6. Molybdate ion and related compounds are the main migrating forms no matter in silicate melt or hydrotherm. While Mo can heavily transport in MoO2Cln2-nn(1≤n≤2) in high salinity hydrotherm; vapour-phase transport of Mo is important for formation of molybdenum deposits, Mo may transport in the gaseous form of MoO3·nH2O(g) and MoO2Cl(g) in low (<-1) and high (>-1) value of logf conditions respectively. Which provide a new explanation for the differences of distribution of molybdenite in sericitic or potassic alteration assemblages in porphyry Mo deposits; The Mo complexes in migration will decompose resulting in the precipitation of MoS2 when Salinity, temperature and pressure decreased, pH value elevated, fO2 value decreased and fS2 value increased. Wall rock alteration, fluid boiling and mixing are the important mechanisms for precipitation of Mo and can enrich metals efficiently.
Keywords: Molybdenum geochemistry partition coefficient migration vapour migration enrichment mechanism
*Corresponding Author, E-Mail: zhdehui@cugb.edu.cn
Bulletin of Mineralogy, Petrology and Geochemistry Vol. 34, No.1, 2015, page 208
