摘要
“沉积型稀土”是在贵州新发现的一种新类型稀土资源。本次研究通过对赫章辅处地区进行地质调查、精细剖面测量及剖面岩石的元素地球化学分析,总结富稀土岩系不同岩性段地球化学特征并推断其物源。结果显示,赫章辅处地区富稀土岩系分布稳定,按岩性可划分为:铁质岩段、铝质岩段与碎屑岩段,稀土超常富集出现在铝质岩段底部与碎屑岩段,且杂色铝质黏土岩中含量最高,ΣREE(不包括Y和Sc)含量为2542.17×10^(-6),达到工业品位。该地区富稀土岩系主量元素主要为SiO2、Al_(2)O_(3)和Fe_(2)O_(3),三者含量之和为78.28%~84.45%,均值为81.13%;TiO_(2)含量相似,其他相容元素明显很低。同时,该岩系亏损大离子亲石元素Rb、Ba、K、Sr、P,而具较稳定含量的高场强元素Zr、Hf、Nb、Ta、Th、U。铁质岩段、铝质岩段及碎屑岩段样品的稀土元素配分模式与玄武岩段类似,均为轻稀土元素富集、重稀土元素平坦,δCe、δEu均小于1,显示弱的负异常。主量、微量、稀土元素相关分析表明,辅处地区玄武岩上部地层的物源主体来自峨眉山玄武岩,超常富稀土岩系(铝质岩段与碎屑岩段)的物源部分来自中酸性火山灰。
The"sedimentary type REE resource"i s a n ew t ype of REE resource found in Guizhou Province.Based on geological survey of the Fuchu area,and detailed profile measurement and geochemical analysis of rocks of the profile in the Fuchu area,Hezhang County,we have summarized geochemical characteristics of samples from different lithologic segments of the REE-rich rock series and then have inferred the provenance of REE-rich rock series.The results show that the REE-rich rock series is stably distributed in the Fuchu area.They can be classified into ferruginous,aluminous and clastic rock segments.The supernormal REE-enriched anomalies occurred at the bottom of aluminous rock segment and in the clastic rock segment.The variegated aluminous claystone has the highest REE content of 2542.17×10^(-6) which is matched the industrial grade.The REE-rich rock series mainly have major elements of SiO2,Al_(2)O_(3) and Fe_(2)O_(3),with sums of their contents ranging from 78.28%to 84.45%,and an average value of 81.13%.Their different rocks have similar TiO_(2) contents,and they have obviously low contents of other compatible elements.In the same time,they are depleted in large ion lithophile elements(LILE)including Rb,Ba,K,Sr and P are depleted,while they have relatively stable contents of high field strength elements(HFSE)including Zr,Hf,Nb,Ta,Th and U.Samples of the ferruginous,aluminous and clastic rocks have similar REE distribution patterns to that of the basalt,as they all have LREE-enriched and HREE-flat patterns,with weakly negative Ce and Eu anomalies as theirδCe andδEu values are less than 1.Correlation analysis of major,trace and rare earth elements shows that the provenance of upper stratum above the basalt in the Fuchu area was mainly sourced from the Permian Emeishan basalt.Especially,the supernormal REE-enriched rock series(aluminous and clastic rock segements)were not only sourced mainly from the Emeishan basalt,but also sourced partly from the intermediate acidic volcanic ash.
作者
罗香建
覃英
卢树藩
符宏斌
刘国栋
陈武
LUO Xiang-jian;Qin Ying;LU Shu-fan;FU Hong-bin;LIU Guo-dong;Chen Wu(Guizhou Geological Survey,Guiyang 550018,China)
出处
《矿物学报》
CAS
CSCD
北大核心
2023年第6期758-770,共13页
Acta Mineralogica Sinica
基金
科技厅重大科技工程项目(编号:黔科合找矿战略[2022]ZD004)。
关键词
物源
地球化学
沉积型稀土
赫章
provenance
geochemistry
sedimentary type REE resource
Hezhang
