Extraction Of Comprehensive Prospecting Information And Metallogenetic Prognosis Of Sn-Polymetallic Deposit In Yichun City,Heilongjiang Province

The Sn polymetallic deposit of Quanhe forestry centre is located in the middle of the Lesser Khingan-Zhang Guangcailing non-ferrous metal metallogenic belt,which is one of the important polymetallic ore belt in Heiongjiang province.The Sn-polymetallic deposit of Quanhe forestry centre mainly produces hydrothermal Fe-Cu polymetallic deposit and hydrothermal Sn polymetallic deposit.The hydrothermal Fe-Cu polymetallic deposit is mainly produced in the contact zone of Qianshan group marble and the Late Triassic granite and its vicinity.The main hosted-alteration is the tourmaline skarn alteration,the actinolite skarn alteration,the epidotization,the silicification and the sericitization.The mineralization is strictly controlled by the contact zone.According to the mineral assemblage and interspecific relationship,the metallogenic process can be divided into two stages:the wet skarn stage is the main ore-forming stage of the iron ore,and the quartz-sulfide stage is the main ore-forming stage of the copper mine.The study of fluid inclusions shows that the quartz inclusions of quartz-sulfide phase is mainly composed of gas-liquid two-phase inclusions,the fluid homogeneous temperature is 359-401?,the salinity is 7.58 wt%-15.85 wt%,the density is 0.57-0.66 g/cm3,and the estimated metallogenic pressure and mineralization depth are 0.44-1.02 Mpa,corresponding to the mineralization depth of 0.04-0.1km.Based on the geological characteristics and fluid characteristics,it is considered that the genetic type of the hydrothermal iron deposit is skarn type deposit.Hydrothermal Sn polymetallic deposit is mainly produced in the Late Triassic granite,and its mineralization is strictly controlled by the fault structure.The hosted alteration is mainly greisenization,followed by beresitization.The metallogenic process is divided into three stages,in which the greisenization stage?stage??is the main metallogenic stage of SnO₂.Our preliminary analysis shows that the hydrothermal Sn deposit is a greisenization-type and high-T vein-type deposit.In the prospecting geological information,skarn-type Fe-Cu polymetallic deposits should be explored in the contact zone and its vicinity between Qianshan group Marble and the Late Triassic granite,and high-T hydrothermal vein type Sn deposits should be explored in the greisenization alteration fracture zone in the granite distribution area.In the prospecting Geophysical information,the apparent resistivity gradient bands are Series of beads-like magnetic anomalies,while showing high magnetic,medium-low resistance,high polarization geophysical abnormal distribution areas are skarn type Fe-Cu polymetallic mineralization favorable areas,and Low magnetic,medium-low resistance,and high polarization geophysical abnormal areas are hydrothermal Sn polymetallic mineralization favorable areas.In the prospecting Geochemical information,the good anomalies Coincidence distribution area in 1:20 0000,1:50000 and 1:20000 geochemical survey are the Cu polymetallic mineralization is favorable areas,while the overlap anomaly areas of Sn,Pb,Zn and As are Sn mineralization favorable areas.The exploration area has a certain Sn,Fe and Cu polymetallic prospecting potential,mainly in the following aspects of the evidence.?1?We identified 1:200000 Ht-5,8,12 soil abnormalities are caused by mineralization.?2?The Fe-Cu ore body and Sn ore body scale has not yet been controlled,Both south and north edges magnetic anomalies from 1:20000 high magnetic precision magnetic measurement are not closed.?3?1:50000 aeromagnetic display magnetic anomaly appear a wide outward range of extension,the north of which found magnetite stones.