中文摘要: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。
Abstract: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 an d 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.
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基金项目: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)和国家 大学生创新性实验计划
引用文本:
胡沛青,任立业,傅飘儿,张铭杰,李晓亚,秦宏毅.2010.新疆哈密黄山东铜镍硫化物矿床成岩成矿作用[J].矿床地质,29(1):158~168.2010.Petrogenetic and ore_forming processes of Huangshandong Cu-Ni sulfide depo sit in Hami, Xinjiang[J].Mineral Deposits29(1):158~168
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