Application of groundwater–mineral equilibrium calculationsto geochemical exploration for sediment-hosted uranium:observations from the Frome Embayment,South Australia
Application of groundwater–mineral equilibrium calculationsto geochemical exploration for sediment-hosted uranium:observations from the Frome Embayment,South Australia
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DOI：
10.1144/1467-7873/03-027
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发表时间：
2004-05
期刊：
影响因子：
--
通讯作者：
M. Pirlo;A. Giblin
中科院分区：
文献类型：
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作者：
M. Pirlo;A. Giblin
本文考虑解释地下水中铀（U）矿-矿物平衡计算，以帮助了解矿床成因和协助勘探。对最近两次实地采样旅行在南澳的弗罗姆湾地区采集的地下水样品进行了主要和选定的微量元素分析。这些数据与以前公布的数据已被用来构建地下水的平衡状态的地球化学模型。估算了各物种的活性和矿物饱和状态。计算出的物种活动一般在Giblin以前关于类似当地水源地下水的模型中报告的范围内。我们的模型表明，无定形UO 2，而不是矿石矿物coffinite和uranite，是solidU矿物相，是地下水铀浓度的可能控制。UO 2（am）饱和度指数没有显示出系统的变化与矿石品位或矿化的接近。它用于勘探在较小的规模，地下水成分是相似的样品之间的网站和铀矿物存在不同的浓度，是值得怀疑的。矿物饱和度指数提供的信息的固有局限性限制了它们的勘探应用，特别是在高盐度古河道地下水环境中，如在澳大利亚常见的。
This paper considers the interpretation of uranium (U) ore–mineral equilibrium calculations in groundwater to help understand ore genesis and assist exploration. Groundwater samples collected on two recent field sampling trips in the Frome Embayment region of South Australia have been analysed for major and selected trace elements. These data together with previous published data have been used to construct geochemical models of the equilibrium state of the groundwaters. Species’ activities and mineral saturation states have been estimated. Calculated species’ activities are generally in the range reported in the previous modelling by Giblin involving groundwaters from similar local sources. Our models indicate that amorphous UO2, rather than the ore minerals coffinite and uraninite, is the solidU mineral phase that is the likely control on groundwater U concentration. The UO2(am) saturation index did not show a systematic variation with ore grade or proximity to mineralization. Its use for exploration at smaller scales, where the groundwater composition is similar between sample sites and U minerals are present at various concentrations, is doubtful. Inherent limitations on the information provided by mineral saturation indices restrict their exploration application,particularly in high salinity palaeochannel groundwater environments, such as those common in Australia.