中国主要含镍岩体(带)岩石类型与组构特征  

THE ROCK TYPE AND THEIR FABRIC FEATURES OF MAIN NICKEL-BEARING INTRUSIVE BELTS IN CHINA

作　　者：师占义[1] 洛长义[1] 杨合群 

机构地区：[1]中国地质科学院西安地质矿产研究所,西安710054

出　　处：《西北地质科学》1992年第1期1-16,共16页Northwest Geoscience

摘　　要：甘肃金川、新疆黄山和吉林红旗岭等岩体(带),产有我国的大、中型硫化镍矿床。含镍岩体的岩石类型分为3类7个岩型。其中主要是金川型,为斜长橄榄二辉岩-(含长)二辉橄榄岩-二辉辉橄岩型,属铁镁质超基性岩体;黄山型,为辉长岩-(橄榄)辉长苏长岩-(含长)二辉橄榄岩型,属铁镁质基性-超基性杂岩体;喀拉通克型,为闪长岩-(苏长)辉长岩-橄榄苏长岩型,属铁质-铁镁质中性-基性杂岩体。岩石矿物组合为贵橄榄石、古铜辉石、顽透辉石、韭闪石、拉-倍长石和少量金云母,附生尖晶石矿物富铁铝、贫镁铬。矿物多为自形晶,中细—中粗粒度。岩石具柱粒结构、堆积结构和熔蚀结构。稀土配分曲线为轻稀土富集—倾斜型,Eu/Sm0.202—0.859,标准化的LREE/HREE>1,系由大陆拉斑玄武质衍生岩浆成岩。岩浆化学成分偏基性,分异充分,单矿物岩相发育,为复合岩体,岩石具富铁或钙铝矿物组合及堆积与熔离结构等,是成矿岩石矿物的主要标志。Intrusive belts in Jinchuan of Gansu, Kalatongke and Huangshan of Xinjiang as well as Hongqiling of Jilin contain nickel sulfide deposits of large and middle scale respectively. The rock type of nickel-bearing intrusions can be derided into three classes and seven typesamong them. The main type is mafic and altrabasic intrusions of Jinchuan type consisting of plagioclase oliv ine websterite—(plagioclase-bearing) lherzolite—pyroxene perido- tite, mafic basic-ultrabasic complexes of Huangshan type consisting of gabbro—(olivine) gabbronorite—(plagioclase-bearing) lherzolite and ferricmafic middle-basic complexes of Kalatongke type consisting of diorite—(norite) gabbro—olivine norite. Mineral assemblages of these rocks are made up of chrysolite, bronzite, endiopside, pargasite, labradorite-bytownite and a small amounts of phlogopite. The associated spinel is rich in iron and aluminium and deficient in magnesium and chromium. The minerals appear mostly idiomorphic and have middle-fine to middle-coarse grade. Prismaticgranular, cumulate and resorption textures are present in the rocks. They show LREE-rich patterns and have Eu/Sm ratios from 0.202 to 0.859, chrondrite-normalized LREE/HREE ratios>1. So they were formed from derived continental tholeiite magmas. The main indicators favarable to mineralization are those rocks inclining to basic, well differentiated, well developed in monomineralic rock phase, and of rather complex which show iron-rich or calcium-aluminium-rich mineral assemblages, cumulative and seg egative textures etc.

关 键 词：岩石 岩体 含镍 类型 组构特征 

分 类 号：P584[天文地球—岩石学]