摘要
金川Ni-Cu-(PGE)硫化物矿床赋存于超镁铁岩体中,是世界第三大镍矿床。金川岩体中部(1#矿体)Ni金属储量约占整个金川矿床的56.8%,岩石呈同心带状分布,矿体横剖面形态为舌状,中间为网状矿石,周围是浸染状矿石,其网状结构矿石丰度远远高于其他矿石类型。1#矿体不同类型矿石亲Cu元素100%硫化物计算后,原始地幔标准化配分模式指示矿石的IPGE具有、高低2个系列的数值特征,Pt变化很大,大部分样品Pt/(Pt+Pd)值在(0.3～0.7)范围之外。钻孔样品Ni、Cu品位的变化指示富Cu矿石富集于网状矿体中、下部,网状矿石的Ni、Cu品位呈明显的负相关关系,Ni/Cu值在深部变化较大。研究认为,1#矿体遭受热液蚀变作用影响明显,矿石IPGE的变化和小尺度的Ni/Cu值循环变化由MSS分离结晶作用所致,矿体中、下部富集富Cu矿石和深部Ni/Cu值变化较大由MSS分离结晶作用和热液蚀变作用综合所致。
The Jinehuan Ni-Cu-（PGE） sulfide deposit is hosted by ultramafic intrusions in northwestern China. It is the third-largest Ni deposit in the world. The central part of the Jinchuan intrusion （Ore Body 1） has a ＂tongue-like＂ shape in cross section and hosts -56. 8% of the known Ni resources. It is character- ized by concentrically zoned, with net-textured ore surrounded by disseminated sulfide. Net-textured ore is dominant over other ore types in ore body # 1. Based on 100% sulfide recalculation, different types of ore in ore body # 1 have high and low value characteristics of IPGE, and Pt vary largely, Pt/ （Pt＋Pd） ratios of most samples are out of （0. 3-0. 7） . The Ni, Cu content variations of drill hole samples indicate that Cu- rich ores concentrated at base of net-texture ore body, and content of this two elements appears obvious negative relationships, Ni/Cu ratios vary largely in deep. This research reveals that the ore body # 1 was affected obviously by hydrothermal alteration. IPGE and small scale variations of Ni/Cu ratios are likely due to fractional crystallization of MSS. Small Cu-PPGE rich lenses and large scale variations of Ni/Cu in the deep part of ore body # 1 may be the result of MSS fractionation or hydrothermal alteration.
出处
《西北地质》
CAS
CSCD
2012年第4期334-345,共12页
Northwestern Geology
基金
国土资源部深部探测技术与实验研究专项(Sinoprobe-05-01)
