摘要
大渡河金矿田是西南地区重要的金成矿集中区,在该区开展稀土元素地球化学特征研究,可为揭示大渡河金矿田成因提供一定的依据。通过含矿石英脉体与围岩的稀土元素特征来探讨康定大渡河流域金矿床的成矿物质及流体来源。采集相关岩矿石样品,测试其稀土元素组成。研究表明,岩矿石均具有轻稀土富集的特征,这是地幔流体作用成矿的标志。含矿脉石英δEu值小于1,是金矿的主要赋存地质体,闪长岩、花岗岩和角闪岩δEu值小于1或约等于1,构成金脉围岩体系。闪长岩、花岗岩和角闪岩稀土配分曲线比较平缓,轻重稀土元素分馏不明显,说明黄金矿矿体与早期围岩无关,属于后期填充,成矿与中新生代造山过程有关。而源于地幔流体的含矿脉石英以及围岩花岗岩具有与地壳相似的稀土元素特征,说明成矿过程中发生了强烈的壳幔物质交换混染。多数样品中Eu亏损并未见Ce异常情况,这说明大渡河金矿床的成矿流体及围岩形成环境具有中高温并且相对氧化性的特征,表明了大渡河金矿床的成矿流体可能属于源于地幔的中高温热液流体。
The Daduhe gold field is an important gold mineralization concentration area in southwest China.Geochemical characteristics of rare earth elements in this area can provide a basis for revealing the genesis of Daduhe gold field.Based on the REE characteristics of ore-bearing quartz veins and wall rocks in Daduhe gold ore field,the significance of REE geochemistry to the metallogenic materials and fluid sources was discussed.Relevant rock and ore samples were selected to test the composition of rare earth elements.The study shows that all rocks and ores are characterized by enrichment of light rare earth elements,which is a sign of mantle fluid mineralization.The quartz Delta Eu value of ore-bearing vein is less than 1,which is the main occurrence geological body of gold deposit.The Delta Eu value of diorite,granite and amphibolite is less than or equal to 1,which constitutes the surrounding rock system of gold vein.The REE distribution curves of diorite,granite and amphibolite are relatively smooth,and the fractionation of light and heavy REEs is not obvious.This indicates that the gold orebody has nothing to do with the early wall rocks and belongs to late filling.The mineralization is related to the Mesozoic-Cenozoic orogenic process.The quartz veins and wall rock granites derived from mantle fluids have the characteristics of rare earth elements similar to those of the crust,indicating that a strong exchange and mixing of crust and mantle materials occurred during the mineralization process.Ce anomaly is not found in most samples with Eu deficit,which indicates that the metallogenic fluids and surrounding rocks of the Daduhe gold deposit have the characteristics of medium-high temperature and relative oxidation,indicating that the metallogenic fluids of the Daduhe gold deposit may belong to the medium-high temperature hydrothermal fluids originating from the mantle.
作者
何阳阳
蒋双宇
李开强
HE Yang-yang;JIANG Shuang-yu;LI Kai-qiang(School of Geography&Resource Science,Neijiang Normal University,Neijiang 641112,China)
出处
《稀土》
EI
CAS
CSCD
北大核心
2020年第1期109-116,共8页
Chinese Rare Earths
基金
四川矿产资源研究中心项目(SCKCZY2016-ZC03)
四川省教育厅科研项目(17ZB0223)
内江师范学院2018年度大学生科研项目(18NSD-112)
内江师范学院大学生创新创业训练计划项目(X2019001).
关键词
稀土元素
地幔流体
金矿
大渡河
rare earth element
mantle fluid
gold mine
Dadu river
