内蒙古大沟井寒武纪黑色页岩元素地球化学特征及钒赋存形式  

Element Geochemistry and Vanadium Occurrence of the Dagoujing Black Shales,Inner Mongolia

作　　者：张红雨 苏犁[1,2] 秦红 ZHANG Hongyu;SU Li;QIN Hong(Institute of Earth Sciences,China University of Geosciences,Beijing 100083,China;State Key Laboratory of Geological Processes and Mineral Resources,China University of Geosciences,Beijing 100083,China)

机构地区：[1]中国地质大学(北京)科学研究院,北京100083 [2]中国地质大学地质过程与矿产资源国家重点实验室,北京100083

出　　处：《现代地质》2022年第1期321-332,共12页Geoscience

基　　金：国家自然科学基金项目(92062219);国有企业委托项目(78932015005)。

摘　　要：对内蒙古大沟井钒矿床的矿石样品进行了系统的常量和微量元素、X射线粉晶衍射以及显微能谱分析,探讨矿石中钒的赋存形式、形成环境以及保存条件等。研究结果表明,矿石样品中P_(2)O_(5)含量变化范围为0.81%~6.14%,显示其磷含量普遍较高,反映地层中较为富集磷;样品烧失量的范围为7.75%~41.24%,比较大,反映云母及泥质胶结物含量较高。矿石的V含量介于1015.2×10^(-6)~4162.0×10^(-6)之间,远高于地壳中钒的平均含量。U/Th值指示样品为正常的海相沉积产物;矿石的V/Cr、Ni/Co、δU、δCe、Ce/La及V/(V+Ni)值的计算结果以及黑色岩系中的大部分Fe均已转化为黄铁矿这些信息一致揭示出,该区黑色岩系整体上形成于一种较干燥、缺氧、富H_(2)S、还原和封闭的滞留海盆环境。矿石样品中钒的主要载体矿物为原生矿物相钒云母,为鳞片状矿物,粒度均极细,多型为2M_(1),矿物化学分子式为K(V,Al,Mg)_(2)AlSi_(3)O_(10)(OH)_(2)。研究认为大量黄铁矿单晶或集合体的存在是钒元素在黑色岩系中富集和保存的有利因素。Systematic analysis of ICP-AES,ICP-MS,XRD and EDS was carried out in this paper to discuss the occurrence and distribution of vanadium as well as formation and preservation conditions of the Dagoujing vanadium deposit in Inner Mongolia.The study showed that P_(2)O_(5) contents ranged from 0.81%to 6.14%,and this high phosphor value indicates the enrichment of P in the strata;LOI values ranged from 7.75%to 41.24%,and this high value indicated that mica and argillaceous cement content were high in samples.Vanadium values ranged from 1,015.2×10^(-6) to 4,162.0×10^(-6),and all the data were much higher than the average composition of the crust.The black shales were classified as normal sedimentary rocks based on the U/Th values;V/Cr,Ni/Co,δU,δCe,Ce/La and V/(V+Ni)values as well as transformation of most of Fe in black shales into pyrite indicated that the black shales in this region formed in a relatively dry,anoxic,H_(2)S-rich,reducing and close basin condition.Vanadium element in samples mainly occurred in roscoelite,which was in very fine phosphorus shape with polytype 2 M_(1) and formula K(V,Al,Mg)_(2)AlSi_(3)O_(10)(OH)_(2).Occurrence of abundant single or aggregate pyrite in rocks created a favorable condition for vanadium enrichment and preservation in black shales.

关 键 词：赋存状态 黑色岩系 钒矿床 大沟井 内蒙古 

分 类 号：P632[天文地球—地质矿产勘探]