摘要
黄山铜镍硫化物矿床镁铁-超镁铁质岩体岩相发育良好,主要包括橄榄岩、辉石岩、辉长岩和闪长岩,橄榄岩中部分橄榄石包含有硫化物珠滴。对该岩体不同岩相进行了主元素、微量元素、铂族元素和单矿物的分析,结果表明,不同类型岩石的化学组成受橄榄石、辉石和斜长石结晶分异作用的控制。微量元素和稀土元素具有相似的分布模式,(La/Yb)N介于1.14～3.65之间,明显亏损Nb和Ta,富集Sr。含矿岩石Cu/Pd和Ti/Pd比值大于原生地幔岩浆。上述结果揭示黄山镁铁-超镁铁质岩体不同岩性的岩石具有不同的主元素和微量元素特征,但母岩浆来自同一源区。根据橄榄石的Fo值和全岩的主要氧化物组成估算出母岩浆为高镁(MgO约为15%)玄武岩岩浆,在岩浆作用过程中地壳富硅组分的混染是导致硫化物熔离的主要机制。
Huangshan Cu-Ni sulfide mafic-uhramafic intrusions show varied petrography, including peridotite, pyroxenite, gabbro and diorite. Some sulfide droplets were found in olivine of peridotite. The major elements, trace elements and platinum group elements （PGE） of whole rock samples of different type rocks, combined with esti- mated MgO content in the parent magma by Fo values of the olivine and the compositions of whole rock, indicate that different type of rocks are mainly controlled in chemical compositions by crystallization of olivine, pyroxene and plagioclase minerals, and display similar trace element and REE patterns. The REE show varied （La/Yb）; ratios, ranging between 1.14 and 3.65. Primitive mantle-normalized trace element distribution patterns display signifi- candy Nb- and Ta-depletion, and Sr-enrichment. The ratios of Cu/Pd and Ti/Pd are higher than primitive mantle values. These evidences indicate that three episodes of mafic-ultramafic intrusions in Huangshan Cu-Ni sulfide deposit with distinctive major and trace elements characteristics, originated from the same source, in which MgO content of the parent magma is about 15%. The metallogenie magma is contaminated by crust components during magmatism. The contamination of Si-rieh crustal component could be responsible for sulphur saturation as well as sulfide melt segregation.
出处
《地球化学》
CAS
CSCD
北大核心
2009年第5期432-448,共17页
Geochimica
基金
国家自然科学基金(40534020
40772058
40873005
40273009)
教育部新世纪优秀人才支持计划项目(NECT-04-0980)
国家科技支撑计划项目(2006BAB01B08
2006BAB01A01)
