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晶质铀矿是一种副矿物,在花岗岩中广泛产出。铀离子价态变化和比值对岩浆氧逸度,有一定的指示意义。本次研究以四川米易海塔地区混合岩中石英质脉体中的粗粒晶质铀矿为研究对象,借助X射线粉晶衍射和X射线光电子能谱测试两种方法,分析样品铀元素价态变化以及对氧逸度的指示意义。X射线粉晶衍射获得样品主要成分为晶质铀矿和少量石英,样品的晶胞参数分别为0.5487 nm和0.5441 nm,计算其含氧系数分别为2.00和2.23。X射线光电子能谱测试分析得到,样品中四价铀的峰值结合能介于380.15~380.46 eV,半峰宽介于1.93~1.94 eV;六价铀的峰值结合能介于381.49~381.98 eV,半峰宽介于1.51~1.92 eV,U^(6+)/U^(4+)比值介于(U^(6+)/U^(4+)=0.13~0.31)。氧逸度热力学计算得到米易海塔地区粗粒晶质铀矿形成时的氧逸度(lgfo_(2))介于-22.12~-21.36。依据近似温度和计算出的氧逸度值,做lgfo_(2)-T协变曲线图。米易海塔地区粗粒晶质铀矿形成时的氧逸度投图数据结果落入FMQ平衡线之上,较为接近MH平衡线。可以推测米易海塔地区与粗粒晶质铀矿共生的石英脉形成时为还原环境。 相似文献
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Environmental Geochemistry of Heavy Metal Contaminants in Soil and Stream Sediment in Panzhihua Mining and Smelting Area,Southwestern China 总被引:4,自引:0,他引:4
Mining and smelting activities are the main causes for the increasing pollution of heavy metals in soil, Water body and stream sediment. An environmental geochemical investiga-tion was carried out in and around the Panzhihua mining and smelting area to determine the ex-tent of chemical contamination in soil and sediment. The main objective of this study was to in-vestigate the environmental geochemistry of Ti, V, Cr, Mn, Cu, Pb, Zn and As in soil andsediment and to assess the degree of pollution in the study area. The data of heavy metal con-centrations reveal that soils and sediments in the area have been slightly contaminated. Geo-chemical maps of Igeo of each heavy metal show that the contaminated sites are located in V-Ti-magnetite sloping and smelting, gangues dam. The pollution sources of the selected elementscome mainly from dusts resultant from mining activities and other three-waste-effluents. The areaneeds to be monitored regularly for trace metal, especially heavy metal enrichment. 相似文献
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金沙江攀枝花段水系沉积物中重金属的分布特征及污染评价 总被引:2,自引:1,他引:2
对攀枝花地区金沙江水系沉积物中九个重金属元素的地球化学特征及空间分布特征进行了分析研究,并对各重金属的污染程度进行了初步评价。研究发现,重金属在支流与金沙江交汇点下游处含量高于上游处,这说明金沙江有一定的自净化能力。通过分析可知,重金属的污染程度为:Cu>V>Ti>Mn>Cr>Zn>As>Co>Pb,其中Cu、V、Ti、Mn污染严重,Pb为轻度污染。污染最严重的地区是攀钢冶金区、攀钢选矿区、攀钢采矿区以及攀钢尾矿坝。 相似文献
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硅质岩作为若尔盖铀矿区重要的含矿主岩之一,铀多于志留系硅质岩中广泛富集,而近年来于寒武系地层中也发现了铀含量较高的硅质岩,目前寒武系含铀硅质岩与区内铀成矿的关系尚不明确,研究这些寒武系含铀硅质岩可以为若尔盖铀矿田铀矿找矿提供新思路、新层位。本文在结合前人研究的基础上,利用镜下观察、地球化学分析等方法对若尔盖铀矿区寒武系硅质岩进行综合分析,探究其成因及其对铀成矿的意义。在地球化学特征上,多数样品w(SiO2)为81.18%~98.55%,平均值高达93.16%,其余氧化物含量除P2O5和CaO较高外均在1%左右或以下;硅质岩Al/(Al+Mn+Fe)为0.16~0.52,Th/U为0.03~0.10,MnO/TiO2为1.2~6.0,δCe为0.530~0.718,LaN/CeN为1.111~2.051,这表明寒武系硅质岩具有热水沉积成因与远洋盆地的形成环境。部分铀含量较高的样品在背散射及扫面图像上观察到的主要矿物为石英和磷灰石,这与样品主量数据反应的高硅、... 相似文献
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