地质论评2017，Vol.63Issue(4)：1050-1063,14.DOI:10.16509/j.georeview.2017.04.016
川西盐边县红格钒钛磁铁矿中镍钴硫化物的铂族元素地球化学特征
PGE Geochemical Characteristics of Massive Sulfide in V—Ti Magnetite at Hongge Area, Yanbian County, Western Sichuan
摘要
Abstract
The paragenesis phenomenon between V—Ti magnetite deposits and sulfide deposits has not yet been found all over the world.Although it was deemed a PGE—Cr enriched layer in the bottom of the ore body at Hongge deposit,the consequence by analyzing lots of drilling samples is not really as the prior viewpoint in Hongge mining area which is in the west of Sichuan province.However,we find the existence of a large amount of massive sulfide deposits ore which can form Fe—Co—Ni paragenetic orebody after piercing into iron orebody in Baicao mining area in at Hongge deposits.The major compositioningredients of massive sulfide ores are pyrrhotite (94％),pentlandite and chalcopyrite,and a few ingredients of augite,sahlite,bronzite,hornblende,phlogopite,magnetite,ilmenite,and andesine,etc.The tenoramount of Ni is 0.72％ ～ 0.90％,while the tenoramount of Co is about 0.10％.These two elements mainly exist in the pyrrhotite.The experimental analysis of Platinum Group Elements indicates that the Cu/Pd ratio is between 12908 and 15109 in massive sulfides,while it is about 24520 in iron ore with 3％ penetrated sulfide.These Cu/Pd ratios are much higher than primitive mantle source value which implies the tiny amounts of sulfide residue in magmatic source.Meanwhile,sulfide phase separations have of the sulfide occurred before the iron ore form.In Hongge area,Pd/Ir ratios of samples ranging from 2.8 to 30,mainly concentrated between 8 and 14,suggestshow it might experience a strong magmatic crystallization.An obvious fractionation phenomenon of Platinum Group Elements in Hongge deposit suggests that sulfide deposit and iron may accumulate simultaneously in fluid.It is difficult to explain the obvious differences of PGE contents by the same magma chamber among different mining areas which can be the product of magmatic evolutions in multi-stage magma chambers.It may imply that there is awill be a subsurface magma chamber where exists Ni—Cu—PGE deposits and Fe—Ti—V deposits in deepth.Methods:Firstly,take 5 to 6 grams of rock powder samples and incorporate a few mixed diluent of platinum,palladium,iridium,ruthenium.Secondly,digest the mixture at high temperatures and pressures with hydrofluoric acid and nitric acid and dissolve it with 6 mol per litre muriatic acid.Then,add in tellurium solution and stannous chloride solution coprecipitation,and the precipitation,after aqua regia dissolving,go through P-507 mixed resin and get rid of the interference elements under acidic medium.Lastly,dry the mixed solution and instill 3 milliliter distilled water and test the compound by Perkin Elmer Elan 9000 ICP-MS machine.Results and Conclusions:(1) Co—Ni Sulfide deposits are initially discovered in Hongge—Baicao dinnings.(2) The content of PGE in Rocks and minerals reduces gradually from north to south which implies that they formed in different periods of magma chamber magmatism.(3) The ratio of Pd/Ir is much lower than the primitive mantle value in Hongge area which indicates that parent magma came from the magma crystallization differentiation.Meanwhile,the sulfide has undergone liquation before the iron ore formed.(4) The obvious fractionation phenomenon of PGE in Hongge deposits explains that the sulfide and iron might accumulate collectively in the early fluid.(5) The vanadium—titanium magnetite in different mining areas in Hongge deposits may formed by multistage magmatic evolution in magma chamber which suggests that deeper magma chamber must exist and deep underground may still have Ni—Cu—PGE deposits and Fe—Ti—V deposits.关键词
红格矿床白草矿段/镍钴硫化物/硫化物珠滴/钒钛磁铁矿/铂族元素Key words
Hongge—Baicao deposit/Ni—Co massive sulfide/Globular sulfide/V—Ti magnetite platinum family element.引用本文复制引用
张腾蛟,李佑国,张月姣,赵伟..川西盐边县红格钒钛磁铁矿中镍钴硫化物的铂族元素地球化学特征[J].地质论评,2017,63(4):1050-1063,14.基金项目
本文为国家自然科学基金资助项目(批准号:41073022)的成果.This study was financially supported by the Natural Science Foundation of China No.41073022) （批准号:41073022）
