Geological Characteristic And Origin Of Deposit In Cuihongshan W,Mo,Zn Polymetatic Deposit

Cuihongshan polymetatic deposit lies in the east of the xing'an-Inner Mongolia fold belt, the west bound of north of the YiChun-YanJi Caledonian fold belt. There are many kinds of granitic instrusives in the mining area, such as alaskite , adamellite , granite porphyry, granodiorite etc.. The mainly strata of this mining area is Lower Cambrian QiShan formation, which is instrusived around by above granitic instrusives.Mineralization heppened in the bounds which the QianShan formation were instrusived by the granodiorites and granitic porphyries and fractures of the surrounding rock. Mainly minerals are magnetite , pyrite , molybdenite , chalcopyrite, scheelite, arsenopyrite, cassiterrite, sphalerite , pyrrhotite ,limonite etc.. Ore structure is mainly shape - half euhedral crystal granular, half idiomorphic - euhedral crystal granular next best. And ore types include compact massive type , disseminated type, briquette-like type and minor stockwork type, breccia type ect.. There are many types of ore, limonite ore, magnetite ore, poor magnetite ore, molybdenum zinc-copper ore, lead oxidation ore, iron lead-zinc ore, molybdenum tungsten ore, granite scheelite ore, and granite lead-zinc mine ore and so on. Alteration of wall rocks associated with mineralization are skarnization, chloritization, grammatitization, epidotization, carbonation etc.. According to different alteration and mineralization, there are three different zone of alteration can be divided, Wo-Sn-Mo-epidote-actinolite zone ,magnetite-epidote-actinolite zone, magnetite- serpentine and galena- sphalerite- chalcopyrite-propylite zone.The granites and grantic porphyries associated with mieralization are high SiO2 (66.11%-77.305%)and rich in Al and alkali but mafic mineral is relative poor. Those rocks rich in LREE and LILS, depleted in HSFE such as Nb , Ta, Ti ,and shown strong Eu negative anomaly. Characeristics of geochemisity suggested that key of tectonic of formation of this deposit is post orogenic extension activity , SunNen block and JiaMuSi Massif were closed by the effect of the pacific plate subduction, partial melting of the lower crust produced intermediate-acid magma and it evoluted above grantic instrusions through fractional crystal. The age of the granitc porphyry instrusions associated with mieralization is 172.3±1.5 Ma (U-Pb) and the age of adamellite is 177.5±2.1 Ma.Ore-forming fluid of Cuihongshan polymetatic deposit is low-medium temperature and low-moderate salinity hytrothermal. Cuihongshan polymetatic deposit is skarn type.The study confirmed the geological mark, geophysical criterion, geochemical marks ,and designate prospecting direction for future.