The Study On Geochemical Characteristics Of Copper-nickel Ore Deposits In Yunnan Funing Basic Rock-ultrabasic Rock Bodies Area

There are about19basic rock-ultrabasic rock bodies in the Yunnan Funing basic rock-ultrabasic rock area,the area is about60Km2.The area is one of favorable area about copper-nickel mineralization in Yunnan Province.With the exploration work during the past60years,there has made some preliminary understanding about the copper-nickel mineralization in this area. But there has a little bit studies about geochemical characteristics of copper-nickel deposit, the origin and evolution of ore-forming fluids and its relationship with mineralization and ore genesis. In this thesis, we mainly through the studies about ore geological characteristics, the major and trace element geochemical characteristics of the deposits, and S isotope geochemistry characteristics of the deposits in the second phase of intrusive rocks, and then combined with regional data and the results of previous studies, comparative analysis of similar geological features in the area. Some important conclusions are obtainted as follows:1、Funing basic rock-ultrabasic rock bodies are tholeiitic series. The transition between facies with magmatic differentiation of fractional crystallization process has provoded an evolutionary trend from the high-K calc-alkaline series to the calc-alkaline series. Trace element analysis results show that the basic rock-ultrabasic rocks are enrichment with LREE.The abnormal of Nb, Ta, and Sr in the rock bodies who have proved that the magma has suffered with crustal evolution. While the S isotope and trace element analysis have providemore to the inference. A lot of evidence suggests that the magma has suffered with crystal fractionation of crustal contamination and the advance important factor is the lead sulfide saturation.2、The main and trace element analysis results show that the magma comes from the mantle. The magmatic liquation and fractional crystallization are the main function of the formation of the ore deposits (mineralization).Magmatic hydrothermal sulfide contributed to the transformation of the prosess, just like conruibutte to sulfide anomalous enrichment in some sections.This has proved that magmatic hydrothermal has an important contribution for the region mineralization. There is pure sulfide vein ore in some section, they has proved that the sulfide-containing slurried along the rock mass fracture zone or fissure penetration and then formed a vein type ore. We have abtained that there may have a deep sulfide magma chamber and magma deep liquation.3、The copper-nickel sulfide deposits (mineralizations) in Funing basic rock-ultrabasic rock bodies has benn strictly controled by the regional deep fault. Deposits (mineralization) have a relationship with pressure-shear structure, especially with the pressure-shear structure. The copper-nickel sulfide deposits mainly hosted by olivine norite gabbro and norite gabbro, and the scale of the orebodies are larger generally.