Fluid Inclusion Characteristics and Genesis of the Kengdenongse Polymetallic Deposit, Qing Hai, China

The Kengdenongshe Au-Pb-Zn polymetallic deposit was located in eastern area of Eastern Kunlun orogenic belt with Paleozoic subduction complex. The geological characteristics of the deposit showed that ore bodies were mainly formed within and adjacent the contact zone of volcanic and carbonate rocks. Two types of mineralization porphyry type and epithermal type have been found. 2 epochs and 5 stages have been divided according to characteristics of the deposit, in which the main mineralization stages werw Pb-Zn (Cu) sulfide stage and barite sulfide stage. One type of fluid inclusions has been identified based on Petrographic and microthermometric criteria, which was a type of two-phased aqueous inclusions. The compositions of cation and anion in liquid and gas of the inclusions were mainly respectively Na⁺, Ca²⁺, K⁺, Cl^-, SO₄^2-; H₂O, CO₂, H₂ and CH₄. The ore-forming fluid was characterized by low salinity (0.17%∼11.34%), and low density (0.50∼1.06 g/cm³), with low-medium temperature of porphyry mineralization ranging from 139 to 320 °C, while the temperature of epithermal mineralization concentrated in two interval, ranging from 150 to 250 °C. metallogenic pressure were estimated to be 0.4∼21.9 Mpa respectively, suggesting that this deposit was formed in a depth of 0.2-0.9 km. Late indosinian orogenic process in the area forming a series of cutting wore metamorphic strata NW-NWW to fracture. Companied with the magmatic activity, Ore forming fluid intrude into the intersection of the faults. At the same time, hydrothermal solution rich in H₂O and CO₂ rise to shallow crust along the crack controlling system. Then the composition and physicochemical poperties of ore-forming fluids were changed, leading to the Lead-Zinc (Copper) Sulfide deposited in the favorable structures. Abstract was to be in fully-justified italicized text as it was here, below the author information.