Study on metallogenic thermodynamic parameters of Lanjiagou molybdenum deposit

doi:10.7523/j.issn.2095-6134.2019.06.012

Abstract

Abstract: The thermodynamic parameters of ore-forming process are the important content of the genesis of the deposits, and the paragenetic minerals inevitably show the metallogenic thermodynamic environment during their formation. Based on this, the mineral assemblages at different metallogenic stages in Lanjiagou molybdenum deposit are evaluated and three mineralization stages are determined. Then the ore-forming temperatures and pressure ranges of the three mineralization stages are obtained by measuring the temperatures of the inclusions, the phase diagrams of the paragenetic compositional minerals at the different mineralization stages are calculated, and the metallogenic thermodynamic parameters of the three metallogenic stages in Lanjiagou molybdenum deposit are estimated. At the stage of quartz phenocryst, the oxygen fugacity ranged from 10^-40 to 10^-25, while the sulfur fugacity ranged from 10^-40 to 10^-5. At the porphyry mineralization stage, the pH value of the ore deposits was about 6.9-6.1, the oxidation-reduction potential was between -1.3 and 0.3 V. At the quartz large vein mineralization stage, the oxygen fugacity was less than 10^-13, the sulfur fugacity ranged from 10^-14 to 10^-6, and the ore deposit was in a weakly reducing environment. All these results help to understand the metallogenic environment of Lanjiagou molybdenum deposit.

Key words: Lanjiagou molybdenum deposit, pH value, sulfur fugacity, oxygen fugacity, mineral assemblages, fluid inclusions

CLC Number:

P618.65

GUO Yang, LIU Lidong, CHU Shaoxiong, LI Yongbing, YAN Quanren, SHI Yaolin. Study on metallogenic thermodynamic parameters of Lanjiagou molybdenum deposit[J]. , 2019, 36(6): 810-816.

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