US EPA

4833575 

Journal Article 

Ore-forming fluid and evolution of Luming molybdenum deposit, Heilongjiang Province 

Wang LinLin; Sun FengYue; Xu JiuHua; Wang KeYong; Wang Li; Xu QingLin 

2015 

31 

4 

979-990 

WOS:000353869400007 

The Luming molybdenum deposit, located in the Lesser Xing' an Range-Zhangguangcai Range polymetallic ore-forming belt, is mainly hosted in monzogranite. According to mineral assemblages, alteration and crosscutting relationships of the veins, the mineralizing stages of the Luming molybdenum deposit can be divided into three; 1) potassium silicification disseminated mineralization stage; 2) silicified stockwork mineralization stage; 3) chlorite-carbonate stage. Aqueous, gaseous, CH4 (CO2)-bearing and daughter mineral-bearing inclusions coexist in molybdenite quartz veins of Luming molybdenum deposit. The homogenization temperatures of aqueous inclusions are from 133 to 425 degrees C, salinities of 1. 6% similar to 16. 1% NaCleqv. Gaseous inclusions with homogenization temperatures of 243 similar to 500 degrees C, salinities of 1. 2% similar to 14. 1% NaCleqv. Daughter mineral-bearing inclusions with homogenization temperatures of 297 similar to 449 degrees C, salinities of 38. 2% similar to 53. 1% NaCleqv. CH4 (CO2) -bearing fluid inclusions by laser Raman spectroscopic analysis confirmed that the components of bubble phase are dominated by CH,, a few containing a small amount of CO2, with homogenization temperatures of 334 to 437 degrees C. delta(34) range of 4. 5 parts per thousand similar to 5. 7 parts per thousand, shows the sulfur comes mainly from magmatic hydrothermal ore-forming fluid. The hydrogen and oxygen isotope data fall near the magmatic water and drift to the meteoric water in the delta D-delta O-18(H2O) diagram, indicating that ore-forming fluids in main mineralizing stages were magmatic water and mixed with a small amount of meteoric water. The trapping pressures of fluid inclusions are estimated to be 30 similar to 90MPa, and consequently corresponding to a depth of 3 to 9km. The ore-forming fluid was initially a single H2O-NaCl-CH4(CO2) supercritical fluid system with high temperature and medium salinity separated from the magma chamber. The ore-forming fluid boiling happened and multiple types of fluid inclusions captured due to reduced pressure and mixed with different fluids. With the continuous evolution of the fluid and the ore-forming temperature gradually reduced, the metallic minerals constantly precipitate and mineralization. From fluid inclusion study on the Luming molybdenum deposit, the ore-forming fluid may not originate from a single magmatic differentiation, but large-scale mixed fluids as well. The complex tectonic backgrounds also control the molybdenum mineralization. 

Fluid inclusion; Ore-forming fluid; Minerogenesis; Luming molybdenum deposit; Heilongjiang Province