The Study Onore Minerals And Metallogenic Period Of The Shuangjianzishan Sliver Polymetallic Deposit

The Shuangjianzishan sliver polymetallic deposit is located in the northern of Banner of Bahrain,Chifeng city,Inner Mongolia,which is expected the largest silver deposit in China.According to exploration data,it is predicted that the resources of Ag prospect will reach more than 20 thousand tons,which belong to superlarge deposits ever be discovered in the southern Da Hinggan Mountainsof China.It has been highly concerned by the geological community.Although scholars and researchers conducted a preliminary study ofthe basic characteristics,the metallogenic age,silver occurrence and geochemical characteristics,there are still so many disputes on mineralization and metallogenic epoch,which meansthey lack the research on low-grade invasive mineralization which was formed in the early stage.Based on previous studies,we focused on low-grade fine disseminated mineralized ores and used a microscope to study the light plates and slices.With the aid of chemical element diagrams,we conducted research on mineralogy,ore forming minerals ore mineralogy and element geochemistry,discussed the sulfide mineralization characteristics of different periods and different stages of mineralization,mineralization and metallogenicprocess,which as the basic information forfuture research in this mine.The main conclusions are as follows:There are two types of ore mineral assemblages in this deposit: One isthe fine disseminated ore and the ore minerals include pyrite and chalcopyrite,the silver grade is low as generally only a few dozen to more than 200 grams per ton,the other is the fine vein network vein and agglomerate ore andits ore mineral assemblage is mainly galena,sphalerite and pyrite combination,the silver grade is higher,even up to several kilograms per ton.The pyrite which generate in the fine disseminated ore distribute in the quartz veins in black slate as the crystal morphology of single crystal or aggregate,hypautomorphic or others crystal type.The ratio of cobalt to nickel is more than 0.5-2.9 and the silver mineralization is not closely related to lead and zinc mineralization.The pyrite which generate in thefine vein network vein and agglomerate ore is well euhedral,mostly intergrowth with sphalerite and galena in the form of aggregates.The ratio between cobalt and nickel is between 1.55-12.44 and the local is up to 32.Its formation is closely related to magmatic hydrothermal solution,and the silver mineralization is closely related to Lead-Zinc mineralization.Two different types of ore mineral assemblages represent two periods of mineralization.The ore mineral assemblages formed in early stage is the fine disseminated ore,which have wide distribution with low silver mineralization grade.The output of silver is closely related to silicification.The ore mineral assemblages formed in advanced stage is thefine vein network vein and agglomerate ore,which essence is the mineralization hydrothermal activity brings new sulfide mineralization and further enrichment of the original mineralization.Galena and sphalerite exhibit multi-stage mineralization.The mineral assemblage characteristics generally show the trend of high temperature phase to low temperature phase transition.The silver minerals exhibit a trend from complex sulfide minerals to simple silver minerals or simple silver minerals.