新疆哈密黄山东铜镍硫化物矿床成岩成矿作用  

Petrogenetic and ore-forming processes of Huangshandong Cu-Ni sulfide deposit in Hami,Xinjiang

作　　者：胡沛青[1] 任立业[1] 傅飘儿[1] 张铭杰[1] 李晓亚[1] 秦宏毅[1] 

机构地区：[1]兰州大学西部环境教育部重点实验室,甘肃兰州730000

出　　处：《矿床地质》2010年第1期158-168,共11页Mineral Deposits

基　　金：国家自然科学基金(40772058;40534020;40873005和40273009);国家科技支撑计划(2006BAB01B08;2006BAB01A01);教育部新世纪优秀人才支持计划(NECT-04-0980);国家大学生创新性实验计划资助成果

摘　　要：黄山东铜镍硫化物矿床赋存于橄榄岩、苏长岩、辉长岩和闪长岩组成的镁铁-超镁铁质杂岩体中,赋矿岩体包含至少4套岩石组合。不同类型岩石微量元素和稀土元素原始地幔标准化配分模式指示,该矿床明显亏损Nb、Ta、Zr、Hf等高场强元素和Cr元素,富集Sr及大离子亲石元素;(La/Yb)N=1.08～2.70,δEu=0.50～2.57;含矿岩石Cu/Pd比值和Ti/Pd比值大于原始地幔值,表明不同类型岩石是高镁玄武质岩浆在深部分异结晶演化的产物。根据橄榄石和全岩化学组成可估算出母岩浆MgO含量约为12%。成矿岩浆深部演化过程中,富硅的地壳混染组分和外来流体的加入可能促成了岩浆中的硫饱和;深部熔离的不混溶硫化物珠滴被上升岩浆携带,富集在橄榄岩和苏长岩的底部。The Huangshandong Cu-Ni sulfide deposit is hosted by mafic-ultramafic rocks composed of peridotite,norite,gabbro and diorite in at least four intrusive rock assemblages. Mineral chemistry and whole-rock major and minor elements,REE and PGE compositions suggest that primitive mantle-normalized trace element patterns show significant depletion of such high field strength elements as Nb,Ta,Zr and Th as well as Cr,and enrichment of Sr and some large ion lithophile elements; （La/Yb）N=1.08～2.70 and δEu=0.50～2.57. The Cu/Pd and Ti/Pd ratios of ore-bearing rocks are higher than the values of primitive mantle. The above evidence indicates that different types of rocks were produced by fractional crystallization of a high MgO basaltic magma at depth. The MgO content of the parental magma is estimated to be 12% on the basis of olivine and whole-rock compositions. Sulfide saturation in the ore-forming magma might have been induced in the deep chamber by Si-rich crustal contamination and exotic fluids. Immiscible sulfide droplets segregated at depth were carried by ascending magma and concentrated at the bottom of peridotite and norite.

关 键 词：地质学 成矿作用 成岩作用 镁铁-超镁铁质岩体 铜镍硫化物矿床 黄山东 新疆 

分 类 号：P618.41[天文地球—矿床学] P618.63[天文地球—地质学]