Tectonic Lithofacies Mapping, Stress Field Analysis And The Deep Metallogenetic Prognosis In Jinchuan Copper And Nickel Orefield

The Jinchuan copper nickel mine is located in Jinchang City,Gansu province,it is the largest Ni-Cu-PGE deposit in China and the research base of the theory of this type of deposit. In order to further improve the research level of structure of ore field,carried out in the research area“Tectonic Lithofacies Mapping, Stress Field Analysis and The Deep Metallogenetic Prognosis in Jinchuan Copper and Nickel Orefield”,the topic has a very important geological significance and guidance to find the prospecting value.The author took part in the tutor “Xinjiang Lop Nor nickel(copper) ore integrated exploration research area of orefield”and “Jinchuan copper nickel ore field tectonic lithofacies observation”and other items. In ore field structure theory research support,on the basis of ten total length of about 6.5 km of the measurement of the tectonic facies zoning profile,map “Tectonic facies mineralization diagram Jinchuan copper-nickel mine”, combined with the analysis of rock, mineral and geochemical tests,by means of the analysis of tectonic stress field, the characteristic of ductile brittle deformation and the study of diagenetic tectonic environment, according to this,the new data of the structure correction of the mineralization depth 5-6Km is proposed, for the deep formation of rock and mineralization and deep prediction,Provided a new reference. The paper has made the following main understanding and progress:(1) According to the secondary development of rock geochemical data, shows that the original magma from continental margin rift picritic tholeiitic basalt,belonging to the high Mg basaltic magma.The δEu=0.38~0.99 in numerous samples shows that the whole area of the mining area has a certain negative Eu anomaly. In addition, loss of Nb content in the rare earth distribution model, which indicates that the mineralization process has undergone crystallization differentiation and crustal contamination. PGE standard spider web, has left PPGE enrichment characteristics,also suggests that the mineralization process of liquation crystallization. Sulfur isotope results indicate that the sulfur source is mainly derived from the upper mantle,which may undergo a weak fractionation or crustal contamination.(2) Map 1:10000 “Tectonic lithofacies mineralization in Jinchuan Mining area”,In order to reveal the structure of the mining area and the formation of the metallogenic regularity, the establishment of tectonic lithofacies and identification marks of legend,explore the new research ideas, and puts forward some new achievements.(3) In the observation of the ductile brittle deformation of the main rock minerals,the quantitative analysis data of olivine and quartz are obtained: Lherzolitic alteration 、containing harzburgite、weak potassic granite and unaltered granite mixed total mineral deformation and ductile / brittle deformation rates were 35 ~ 55% 、0.43 ~ 0.57(Brittle- ductile deformation structures area), 45 ~ 55% 、 1.88(ductile deformation structures area), 55~70%、2.12(ductile deformation structures area) and30~45%、2.75(ductile deformation structures area).(4) The tectonic stress field in the region is briefly summarized in this paper,and the analysis of the difference of the ancient stress and the strain of the rock in the olivine and quartz. The results show that the results of strain ratio and the difference of the paleo stress were“1.57、51.58-68.35 Mpa,2.56、43.23-65.21Mpa”.(5) Application of geological thermometer and structural correction method to get the value of the depth of the formation of the olive: On the basis of the research on the rock forming data, the estimation of the depth of the rock is 11.93 to 28.44Km;On the basis of fluid inclusion’s metallogenic pressure and rock deformation structure analysis,the value of jinchuan deposit’s metallogenic depth is-5192.98~-6214.96 m with the tectonic stress correction method.