| There are plentiful mineral resources of nickel, cobalt, and copper in the northwest region of China, specially Jinchuan superlarge copper-nickel sulflde magmatic deposit in Gansu province, known for its large scale and typical metallogenetic feature in the world, is an important source of Ni-Cu metal mineral resource in our country. In contrast, Jianchaling large cobalt-bearing nickel sulflde deposit in Shannxi province is not famous and unmined, but many problems about the deposit are researched because of its special geologic settings and mineralization characteristic. According to the theory and study methods of comparative economic geology, the ore-forming geological background, geological feature, the elements geochemistry, the metallogenic geochronology about the two ore deposits and rock-bodys are systematic analysed, compared, and researched by means of new measure and assay technique. Jianchaling nickel sulflde deposit is stress investigated in order to study similarities and differences between the two deposits in mineralization background, geochimistry, and metallogenesis, also to find the reasons for these, discuss the regularity of formation and distribution for the type deposit, and guide its exploration.On the basis of systematic analysis and comparative research on Jianchaling and Jinchuan nickel sulflde deposit in geology and geochemistry, some conclusions can be drawn as follow:(1) Re-Os isotopic geochronology data define an precise 878 ?6 Ma isochon, suggest Jianchaling nickel sulflde deposit would form in new Proterozoic. The rock-forming process and metal logenesis happened on the whole, this deposit subordinates to magmatic deposit. At the same time, it is proved again that Jianchaling rock-body intruded in new Proterozoic.(2 ) The comparative study on PGE geochemistry indicated that it exists multiple diagenesis and mineralization in Jinchuan superlarge copper-nickel sulflde deposit. However, compared with Jinchuan ore-bearing intrusion, Jianchaling ultrabasic intrusion formed by magma simple emplacement, and magma fractionated weakly with lower content of nickel and sulphur.(3) Jianchaling ultrabasic intrusion belongs to magnesian ultrabasic simple rock-body, close related with Yangzi block in space, which formed in the interim of Proterozoic active tectonic zone to Phanerozoic orgenic belt. Jianchaling nickel deposit that respected with it is originally devided into magma type deposit, its metallogenesis include magma differrentiation-crystalization, sulfurization process, magma melt-segregated, and hydrothermal process. But melt-separated ore-forming poorly developed, and hydrothermal process is subordinate, the assimilation and contamination of country rocks have special significance to the formation of this ore deposit.(4) The comparative research suggests that various types of ultrabasic-basic rocks occurred different geological environment and different intruded mechanism can bring on different types of nickel sulflde deposit. Compared with Jianchaling nickel sulflde deposit, Jinchuan superlarge copper-nickel sulflde deposit mostly related with mafic-ultramafic complex that multiple intruded, spatially respected with old Huabei block, which formed in marginal rift in middle-new Proterozoic. Its metallogenesis also include magma differrentiation-crystalization, sulfurization process, magma melt-segregated, and hydrothermal process, whereas magma melt-segregated ore-forming process played an important role, and hydrothermal process is secondary, too. Substance of rock-forming and ore-forming in both Jianchaling and Jinchuan nickel deposit mainly derived from the upper mantle, but the former source is relatively depleted mantle. On the other hand, there exsisted the crustal contamination during the formation of the two mineral deposits, the later contaminated poorly and gave priority to deep contamination.(5) By the comparative study of Jianchaling with Jinchuan nickel sulflde deposit, it is pointed that small basic-ultralbasic complexes whi...
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