The Characteristics Of Metallogenic Fluid And Depths Of Yaojiagou Porphyry-Mo Deposit In Qingchengzi Town Liaoning Province

The Yaojiagou molybdenum deposit is a new one discovered in recent years of the Qingchengzi ore field,Liaoning. It is located in the northern margin of the North China craton Liaodong rift zone. Discovered molybdenum deposit provides a new direction for geological exploration of the Qingchengzi ore field.Deposit alteration zonation is evident. Are: quartz core, potassic granite belt, epidotization granites and skarn belt. Molybdenum mineralization mainly in potassic zone and skarn zones. Yaojiagou granite have characteristics of a multiple-intrusion. The UST quartz veins and quartz eye is evidence of exsolution Magmatic hydrothermal from Yaojiagou intrusion.We observed six stages fluid activity, Quartz eyes(The early stage) â†'Quartz veins with Molybdenum mineralization(The mineralization stage)â†'Quartz veins without Molybdenum mineralization(The third stage) â†'Calcite veins(The fourth stage) â†'Anhydrite veins(The last stage). The UST quartz veins may be little to do with molybdenum mineralization. There are five types of fluid inclusions. Except pure CO2 fluid inclusions. Fluid inclusions in the early stage, mineralization stage,third stage,fourth stage,last stage and the UST quartz veins yield homogenization temperatures of 211.4~515.4 ℃, 179.5~424.5℃, 167.8~353.3℃, 132.5~234.1℃ and 158.6~381.7℃, and salinities of 0.8~19.2, 2.4~21.5, 3.4~15.8, 0.9~11.2 and 1.6~21.5% Na Cl equivalent, respectively.Raman results show that fluid inclusions containing mainly H2 O. We also found CO2,CO3in fluid and chalcopyrite, goethite, quartz in solid phase. The early stage mid-high temperature fluid is a rich volatile(CO2) system with mid-low salinity, weak alkaline. In the mineralization stage numerous metal precipitated as the temperature, pressure, salinity reduced, CO2 escaping and system restore enhancements. In the third and fourth stage temperature, salinity, CO2 content is further reduced, and oxidation is gradually increased. There are no CO2 fuild inclusions in calcite veins. Finally, the fluid exhibits strong oxidizing and generate anhydrite. Immiscible fluid, wall rock alteration and fluid mixing is the main mechanism of metal element precipitated.We use isometric lines intersect method to estimate trapping pressure, Fluid inclusions in the early stage, mineralization stage,third stage and the UST quartz veins yield Trapping pressure of 220~145MPa, 180~124MPa, 115~60MPa and 148~78MPa, respectively. In the mineralization stage metallogenic depth is estimated to be 7 ~ 4.6km.The hydrogen and oxygen isotope studies show that the fluid in the mineralization stage is maxed by magmatic water and precipitation or metamorphic water...