摘要
赣南地区浅变质岩系分布广泛,且风化壳发育,查明浅变质岩的岩石学及地球化学特征对分析离子吸附型稀土矿床的成矿潜力具有重要作用,而目前关于变质岩离子吸附型稀土矿的研究资料较少。本文对区内广泛发育的新元古代—寒武纪浅变质岩进行采样,通过岩相学、岩石地球化学等方法对赣南浅变质岩进行分类研究。结果表明:赣南浅变质岩时代跨度大,从青白口系至泥盆系以及少量侏罗系均有出露,以新元古代面积最广,主要类型有变砂岩类、变质凝灰岩类、板岩类、千枚岩类及片岩类。其中,变砂岩类和变质凝灰岩类的稀土含量高(∑REEs平均值分别为302μg/g和246μg/g),LREEs/HREEs=2.68~5.43,目前查明的稀土矿物主要为独居石和磷钇矿。区内变质凝灰岩类产出厚度较大,稀土含量较高,风化壳发育,是良好的离子吸附型稀土矿的成矿母岩类型。千枚岩类和片岩类的平均稀土含量(∑REEs>224μg/g)次之,但由于岩石风化难度较大,形成稀土风化壳型矿体可能性偏低。本研究是对变质岩离子吸附型稀土矿成矿的初步探讨,旨在为今后进一步的研究和找矿工作提供基础资料和依据。
Epimetamorphic rocks and related weathered crusts are widely distributed in South Jiangxi province.Identifying the petrological and geochemical characteristics of epimetamorphic rocks has a significant effect on the metallogenetic potential analysis on ion-adsorption REEs deposits.At present,there is little research about the metamorphic rock ion-adsorbed rare earth deposits.Epimetamorphic rocks of Neoproterozoic to Cambrian age are widely distributed in this region.Petrological and geochemical methods are used to classify these epimetamorphic rocks.Results show that the epimetamorphic rocks in this region have a large age span,ranging from Qingbaikou to Devonian.Minor epimetamorphic rocks also occur in Jurassic strata.Neoproterozoic epimetamorphic rocks are most widespread and mainly include blastopsammite,metamorphic tuff,slate,phyllite,and schist.Blastopsammite and metamorphic tuff have the highest REEs content with average contents of 302 μg/g and 246 μg/g,respectively,and show the LREE enrichment patterns with LREEs/HREEs of 2.68-5.43.Monazite and xenotime are the two most common rare earth minerals found in the epimetamorphic rocks so far.The metamorphic tuffs in the area have a large outcrop thickness,high REE content and well-weathered crusts,which are good metallogenic parent rocks for ion-adsorbed rare earth deposits.Phyllite,schist and granulite have lower REE contents(> 224 μg/g,on average),but they are resistant to weathering and thus have a low potential in forming REE ore bodies.This study was a preliminary discussion of ion-adsorption rare earth deposits related to epimetamorphic parent rocks,which provides basic information and reference for further studies and prospecting.
出处
《岩矿测试》
CAS
CSCD
北大核心
2018年第1期96-107,共12页
Rock and Mineral Analysis
基金
中央级公益性科研院所基本科研业务费专项基金＂赣南变质岩离子吸附型稀土矿成矿规律与找矿方向研究＂(YYWF201527),＂赣南变质岩离子吸附型稀土矿成矿机理研究＂(K1506)
中国地质调查局地质调查项目＂华南重点矿集区稀有稀散和稀土矿产调查＂(DD20160056)
关键词
浅变质岩
稀土元素
风化壳
离子吸附型稀土矿
X射线荧光光谱法
电感耦合等离子体质谱法
epimetamorphic rock
rare earth elements
weathered crust
ion-adsorption REE deposit
X-ray Fluorescence Spectrometry
Inductively Coupled Plasma-Mass Spectrometry
