摘要
大塘矿段位于贵州瓮福磷矿白岩矿区,矿体(层)赋存于震旦系陡山沱组(Pt_(3)^(3)d),根据成矿的先后时间,该矿段形成了a矿层(下矿层)、b矿层(上矿层)2个矿层,矿层中间为一白云岩G夹层,是典型的海相沉积碳酸盐岩型磷矿床。为深入研究该矿段磷矿床的稀土元素地球化学特征,文章通过野外地质调查、光学显微镜观察、X射线荧光光谱(XRF)与等离子体质谱(ICP-MS)、扫描电镜与能谱(SEM-EDS)等实验方法对其进行了较系统的分析。研究结果表明,a、b矿层磷矿石的δCe、δEu呈负异常,b矿层较a矿层负异常值更明显,且Y/Ho比值由a矿层到b矿层逐渐升高,同时结合Ce_(anom)-Nd关系图,均反映出由a矿层到b矿层的形成环境是由相对还原环境转变为相对氧化环境。b矿层稀土元素PAAS标准化模式曲线较为一致,为中稀土元素略富集的帽状形态,反映磷矿形成过程中明显有生物或有机质参与;b矿层形成过程中经历了较强的水动力搬运,沉积速率较高,沉积时间较短,其ΣREY较a矿层低。大塘矿段a、b两个矿层磷矿石中Y等大部分稀土元素都主要以类质同象形式赋存于胶磷矿中。
Datang oreblock is located in Baiyan mining area of Wengfu phosphorus deposit,Guizhou Province.The ore body(layer)occurs in Doushantuo Formation of Sinian(Pt_(3)^(3)d).According to the formation time relationship of ore beds,the ore bodies of the Datang oreblock can be divided to the bed a(the lower ore bed)and bed b(the upper ore bed),with an interlayer dolomites G between them,and it is a typical marine sedimentary carbonate type phosphorus deposit.The geochemical characteristics of associated rare earth elements in Datang oreblock are mainly analyzed through field geological survey,optical microscope,scanning electron microscope energy spectra(SEM-EDS),X-ray fluorescence(XRF)and inductively coupled plasma mass spectrometry(ICP-MS).The analysis results show that the δCe,δEu shows negative anomaly,and the negative anomaly value of ore bed b is more obvious than that of ore bed a,and the Y/Ho ratio gradually increases from ore bed a to ore bed b.At the same time,combined with the projection diagram of Ce_(anom)-Nd,it reflects that the formation environment from ore bed a to ore bed b is transformed from a relative reduction environment to a relative oxidation environment.The PAAS standardization model curve of REE in ore bed b is relatively consistent,which is a cap shape with slightly enriched middle REE,reflecting the participation of biological obvious or organic matter in the formation of phosphate rock;During the formation of ore bed b,it experienced strong hydrodynamic transport,with a higher deposition rate and a shorter deposition time,and itsΣREY was lower than that of ore bed a.Most of the rare earth and Y elements in phosphate rock mainly occur in collophanite by isomorphism or adsorption.
作者
梁坤萍
何明勤
田欢欢
LIANG KunPing;HE MingQin;TIAN HuanHuan(College of Resources and Environmental Engineering,Guizhou University,Guiyang 550025,Guizhou,China;Key Laboratory of Karst Georesources and Environment,Ministry of Education(Guizhou University),Guiyang 550025,Guizhou,China)
出处
《矿床地质》
CAS
CSCD
北大核心
2024年第2期443-462,共20页
Mineral Deposits
基金
国家自然科学基金资助项目(编号:U1812402和41563003)资助。
关键词
地球化学
稀土元素
大塘矿段
瓮福磷矿
geochemistry
rare earth elements(REE)
Datang oreblock
Wengfu phosphorus deposit
