| This paper takes the graphite deposit in Chulute area,Wulan County,Qinghai Province as the subject.The filed geological characteristics of graphite deposit was detailed observed,the petrological characteristics of graphite ore were discussed with the study on petrographic formations of ore-bearing rock,and the geochemical characteristics of graphite deposit was understood by chemical analyzed method.Then,based on the identification of light and thin sections under microscope,the deposit genesis,metallogenic regularities and controlling factors of graphite deposit were comprehensive analyzed.This study enriches the metallogenic theory in Wulan area,strengths the research on the metallogenic prediction and metallogenic regularity of graphite ore,further improve the development and utilization of capacity of graphite mineral in Wulan Area,and contributes to create values for the development of national economy.Based on the “from the known to the unknown,from the points to surface,surface development,selective inspection,key breakthrough” principles and the clues of graphite-bearing marble mineralized bodies,the mineralized bodies in the area were further searched and recovered by route geological survey,geological survey,geophysical survey and other methods.Then,by the means of shallow drilling,trench construction and groove sampling,further control was carried out to delineate the mineralized bodies,thus further delineating the graphite marble ore bodies.The graphites deposit is located in located in the eastern part of the continental margin arc of Erashan of the eastern Kunlun Arc Basin of the Qi-Qin-Kun Orogenic System,and is the deposit type on the edge of crystalline basement.The deposit is characterized by active belt type,and is linear distribution.It is a type of heat flow metamorphism in the medium-temperature and medium-pressure region,and the graphite flake formed is large.The outcrop zone in the mining area is mainly the lower rock group of paleo-boundary gold spout,including gneiss formation and marble formation.Gneiss components are distributed in most areas of the working area,and the lithology is amphibole plagioclase gneiss with partial marble and variable sandstone.Marble formation is mainly distributed in the north and east of the work area,from northwest to southeast,and the lithology is marble with gneiss.The original rocks of metamorphic rocks in the working area may be argillaceous,argillaceous calcareous and carbonate materials deposited in the environment of frequent oscillation of sea water according to the occurrence of strata in the mining area,the characteristics of rocks,rock and mineral assemblage as well as the characteristics of petrochemistry.Based on the chemical analysis and microanalysis of rock samples,it is concluded that the carbon sources of graphite deposits in Chulute Area are mainly organic carbon deposition and metamorphism.The research is in the work area of 21 mineralization,all of which are marble crystalline graphite with and the mineralizationof about 2-36 m and the extension of about 50-9600 m.In addition,19 ore bodies with thickness of 2.09-23.03 m and length of 465-2056 m have been demarcated in each mineralization body,which are distributed in lensform or stratiform with grade of 2.7-12.43% and average 6.92%.Finally,the arithmetic mean method was used to estimate the graphite ore resources of 15.4264 million tons and the graphite mineral resources of 0.8912 million tons.Through this research,the graphite ore mineralization mechanism in Chulute Area in Wulan county is as follows.Carbonate rocks are commonly developed in the lower paleo-boundary gold reservoir group,which provides good material conditions for the formation of graphite ore.It has been found that that the multiphase metamorphism in the working zone in the lower paleo-boundary and the strong magma activity and tectonic activity in the area surrounded has also provides a good modification and thermal condition for the formation of graphite deposit.In addition,as the occurrence of the rock,the graphite-bearing dolomitic marble,within the working zone is consistent with the surrounding rock,it is believed that the graphite-mineralization in the working zone is formed by sedimentary metamorphism superimposed thermal metamorphism of carbonate rocks containing higher organic matters. |
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