摘要
黔西北玉龙地区稀土含矿层(Pxt)处于宣威组(P_(3)x)底部,假整合于峨眉山玄武岩组(P_(2-3)em)之上,是一套富集了Nb、REE的铁质、铝质黏土岩。研究表明,铁质段与玄武岩微量元素、稀土元素配分曲线形态基本一致,说明铁质段与峨眉山玄武岩具亲源性,主量元素投点反映出铁质段物源主要由峨眉山玄武岩提供。铝质段与玄武岩微量元素、稀土配分曲线存在差异,且主量元素投点显示铝质段物源具多源性,表明除峨眉山玄武岩提供物源外,还有部分中酸性岩浆物质提供部分物源。铁质段和铝质段均呈轻稀土富集型,铝质段富集程度更高,轻稀土元素中La、Ce、Pr、Nd富集明显,占轻稀土元素的85.76%~98.36%,重稀土元素中Gd、Dy、Er、Yb富集较明显,占重稀土元素的84.41%~89.33%。铁质段形成于水动力较弱的氧化环境,铝质段形成于水动力强-弱交替的氧化-还原界面,CIA、CIW、ICV值反映铁质段、铝质段经历过强烈的风化改造作用。
The REE ore-bearing layer(Pxt)in the Yulong area of the northwestern Guizhou is distributed at the bottom of the Xuanwei Formation(P_(3)x),and overlaied discomformably above the Emeishan basalt Formation(P_(2-3)em).It is composed of Nb-and REE-enriched ferruginous and aluminous claystones.The research shows that the distribution patterns of trace elements and rare earth elements of the ferruginous claystone are nearly consistent with those of the basalt,indicating that the ferruginous claystone has affinity with the Emeishan basalt.The projection plots of major elements reflect that the material of ferruginous claystone was mainly sourced from the Emeishan basalt.There are differences between distribution patterns of trace elements and rare earth elements of the aluminous claystone and those of the basalt.In addition,the projection plots of major elements show that the aluminous claystone has multiple material sources.These mean that in addition to the Emeishan basalt,the intermediate acidic magmatic materials had also provided part of source materials for the aluminous claystone.Although both ferruginous and aluminous claystones have light rare earth elements(LREE)-enriched distribution patterns,the aluminous claystone has higher LREE-enriched distribution patterns comparing to the ferruginous claystone.Comparing to others of the LREE,La,Ce,Pr and Nd are more obviously enriched as they are accounted for 85.76%-98.36%of the LREE,Comparing to others of heavy rare earth elements(HREE),Gd,Dy,Er and Yb are more obviously enriched as they are accounted for 84.41%-89.33%of the HREE.The ferruginous claystone was formed in an oxidation environment with weak hydrodynamic force,while the aluminous claystone was formed at the oxidation-reduction interface with strong and weak alternated hydrodynamic force.The values of CIA,CIW and ICV reflect that the ferruginous and aluminous claystones had undergone strong weathering and reworking processes.
作者
薛洪富
黄威虎
曾道国
黄智龙
金中国
罗泰义
吴林
向震中
XUE Hong-fu;HUANG Wei-hu;ZENG Dao-guo;HUANG Zhi-long;JIN Zhong-guo;LUO Tai-yi;WU Lin;XIANG Zhen-zhong(Institute Geology and Mineral Exploration,Non-ferrous Metals and Nuclear Industry Geological Exploration Bureau of Guizhou,Guiyang 550005,China;Non-ferrous Metals and Nuclear Industry Geological Exploration Bureau of Guizhou,Guiyang 550005,China;Stake Key Laboratory of Ore Deposit Geochemistry,Institute of Geochemistry,Chinese Academy of Sciences,Guiyang 550081,China)
出处
《矿物学报》
CAS
CSCD
北大核心
2023年第6期771-785,共15页
Acta Mineralogica Sinica
基金
贵州省地勘基金项目(编号:2021-01号)
贵州省找矿突破战略行动重大协调创新项目(编号:[2022]ZD004)。
关键词
稀土含矿层
地球化学特征
峨眉山玄武岩
黔西北
rare earth elements(REE)ore-bearing layer
geochemical characteristics
the Emeishan basalt
northwestern Guizhou
