| This paper based on the mineral survey project that is belong to Central Geological Exploration Fund Management Center.Combined with regional geology and geological data of the deposit,this paper identifies basic characteristicsof geological and tectonics in the QuanYan-ShuangXingsidui area.Furthermore,this paper confirms the main ore controlling factors,including the approximate distribution range,number of ore bodies,scale,shape,occurrence and ore quality,and then concludes the regularity of ore-forming and further prospecting.The study area is located in Daquanyuan town of Tonghua,Qinghe Town and Caiyuan Town of Ji'an city,The tectonic location is lied in the southern end of the North China Craton,the northern end of the Jiaodong ancient block,south Liaohe-Qinglong Rift Valley and west ji'an-linjiang Paleoproterozoic Rift Valley,which is the ancient metamorphic area of the Paleoproterozoic and the Liaodong-Jiannan metallogenic belt(Au,Pb,Zn,Fe,Ag,B).The metallogenic belt is a concentrated area of crystalline graphite mineralization.On the basis of geological exploration,predecessors found one crystalline graphite mineral field on theQuanYan-ShuangXingsidui area of Ji'an City.This mineral exists in graphite biotite plagioclase gneiss and graphite diopside granulitite,which belong to the first or third section of the Huangchagou formation in Ji'an Group.Through the original rock recovery,we find that the original rock of Huangchagou Formation is composed of basic basalt,Intermediate acid volcanic debris rock,carbonate rock and Sandy sedimentary rock,which belong to debris and carbonate sedimentary formation with the characteristics of lysch formation.The original rockformation consists of terrigenous debris,clay rock,carbonate rock and basic volcanic rocks.The metamorphic degreeof ore-bearing rock is mainly amphibolite facies that belongs to medium-pressure region.Folds and faults of the deposits are well developed,which usually accompanied by late granites,pegmatite intrusion andmigmatization.It is obvious effect of multi period metamorphism.The ore body is controlled by sedimentary metamorphismand has a certain horizon,and its occurrence is consistent with that of surrounding rock.The later metamorphism has some influence on the local enrichment and recrystallization of carbon,and even destroys the characteristics of the original rocks.However,the grade level and distribution of graphite ore are still mainly depending on the original deposition conditions and paleogeographic environment.Based on the analysis of ore-forming geological condition of crystalline graphite mineral deposits,this paper concludes the main reasons and prospecting indicators of crystalline graphiteformation.(i)Stratigraphic indicator: It is an important symbol to search graphite biotite plagioclase gneiss and graphite diopside granulitite,which belong to the first or third section of the Huangchagou formation in Ji'an Group.(ii)Sedimentary formation and ore-forming conditions: the original rock consists of terrigenous debris,clay rock,carbonate rock and basic volcanic rocks.The metamorphic amphibolite facies is an important symbol to find crystal graphite ore.(iii)Lithology indicator: including all kinds of graphite-bearing rock,gneiss,granulite and marble.(iv)Geophysical characteristics:low resistivity and high polarizability anomaly can offer some help to find graphite ore.Graphite is good conductive minerals,so that there is obvious electrical difference between mineralization and the surrounding rock.The range of abnormal excitation is usually consistent with the graphite-bearing strata,and its abnormal intensity may reflect the amount of graphite to in a certain extent.Based on systematic research on the crystalline graphite mineral in the Quanyan – ShuangXingsidui area of Ji'an City,and combined with tectonic setting,the characteristics and genetic model of the ore deposit,we forecast and delineate the one mineralization prospect areas in Yaoying belts that located in the northeast of study area. |
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