Mineralization Study Of Yangliuping Cu-Ni Sulphide Deposit In Sichuan Province

The object of the study was Yang liuping's copper nickel sulfide deposit.We focus on the key petrology issues magmatic sulfide deposits:the nature of magma source of primary magma,whether the intrusion has underwent crustal contamination or not and the degree of the crustal contamination.The study of the intrusions were carried out based on petrology,minieralog,element geochemistry,isotope geochemistry.The following are the main results:(1)The previous obtained the age of 250.2±1.9 Ma by testing the weakly metamor-phic basic and ultrabasic rocks of flogopite in the Qel,presuming the deposit Being the product of Permian Emei mantle plume.Re-Os isotopic analyses of Ni-and Cu –bearing pyrrhotite from the deposit have been used to deternming the timing of mine-ralization,the source of osmium,and by inference,the source of ore metals.Analyses of these data yield a isochron with an age of 375±63Ma(MSWD=9.2).The Age implies that the Cu-Ni sulfide deposit formed different with the main eruption phase of the Emeishan large igneous province.The data also indicate that it is a separate metallogenic events.According to their age and the trace element tectonic environment discrimination diagram preliminary concluded that the formation of the deposit environment of island arc environment.(2)The Si O2 and major element oxides have a good correlations which indicate the fractionation olivine and gabbroic assemblage.The correlations of Mg O and major element oxides indicate dominant olivine fractionation in the ultramafic unit,and fractionation of a clinopyroxene and orthopyroxene in the mafic units.The correlations of ?Eu and major element oxides and Sr indicate the fractionation gabbroic assemblage.(3)That S isotopic composition range is not big,Show a high degree of ore-forming materials of homogenization.The composition range of S isotopic-2~+2‰ suggests Sulfur mainly come from the mantle;The higher initial ratio of the 87Sr/86 Sr,The initial ratio of the187Os/188Os(0.1469 ± 0.0037),the value of the ?Os(26~46),The larger ratio change of 208Pb/204 Pb and the ratio of the Nb/U and the Ce/Pb indicate the assimilation of the crustal material contamination.