Origin of middle rare earth element enrichments in acid waters of a Canadian High Arctic lake
Origin of middle rare earth element enrichments in acid waters of a Canadian High Arctic lake
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DOI：
10.1016/s0016-7037(98)00291-9
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发表时间：
1999-01-01
影响因子：
5
通讯作者：
Zhou, XP
中科院分区：
文献类型：
--
作者：
Johannesson, KH;Zhou, XP
中稀土元素（MREE）富集的岩石归一化稀土元素（REE）模式的稀酸性湖（颜色湖）在加拿大北极高，进行了研究，通过量化全岩稀土元素浓度的岩石样品收集的集水盆地，以及确定酸浸出稀土部分这些岩石。每个岩石样品的等分试样用1 N HNO 3浸出，以检查每个岩石的容易浸出的REE部分，另外的等分试样用0.04 M NH 2 OH浸出。HCl的25%（v/v）CH 3COOH溶液，专门用于还原Fe-Mn氧化物/羟基氧化物。稀土元素与弹性沉积岩样品反应，岩石学上可识别的铁锰氧化物/羟基氧化物水泥和/或矿物/无定形相，表现出全岩正常化稀土元素模式类似的湖泊沃茨，而全岩正常化的镁铁质火成岩和其他弹性沉积岩从集水盆地的沥滤液从湖沃茨有很大不同。全岩，沥滤液，湖水稀土元素数据支持酸浸或溶解的MREE富集铁锰氧化物/氢氧化物，并确定在一些集水盆地沉积岩作为独特的湖水稀土元素模式的可能来源。流入河流和湖泊沃茨中稀土元素的溶液络合模型表明，游离金属离子（例如，Ln（3+）和硫酸盐络合物（LnSO（4）（+））是溶解态稀土元素的主要形式。因此，溶液络合反应涉及的稀土元素在风化，运输到湖泊，或在湖泊内，不能被调用来解释的MREE富集观察到的湖泊沃茨。版权所有（C）1999 Elsevier Science Ltd.
Middle rare earth element (MREE) enriched rock-normalized rare earth element (REE) patterns of a dilute acidic lake (Colour Lake) in the Canadian High Arctic, were investigated by quantifying whole-rock REE concentrations of rock samples collected from the catchment basin, as well as determining the acid leachable REE fraction of these rocks. An aliquot of each rock sample was leached with 1 N HNO3 to examine the readily leachable REE fraction of each rock, and an additional aliquot was leached with a 0.04 M NH2OH . HCl in 25% (v/v) CH3COOH solution, designed specifically to reduce Fe-Mn oxides/oxyhydroxides. Rare earth elements associated with the leachates that reacted with elastic sedimentary rock samples containing petrographically identifiable Fe-Mn oxide/oxyhydroxide cements and/or minerals/amorphous phases, exhibited whole-rock-normalize REE patterns similar to the lake waters, whereas whole-rock-normalize leachates from mafic igneous rocks and other elastic sedimentary rocks from the catchment basin differed substantially from the lake waters. The whole-rock, leachates, and lake water REE data support acid leaching or dissolution of MREE enriched Fe-Mn oxides/oxyhydroxides contained and identified within some of the catchment basin sedimentary rocks as the likely source of the unique lake water REE patterns. Solution complexation modelling of the REEs in the inflow streams and lake waters indicate that free metal ions (e.g., Ln(3+) where Ln = any REE) and sulfate complexes (LnSO(4)(+)) are the dominant forms of dissolved REEs. Consequently, solution complexation reactions involving the REEs during weathering, transport to the lake, or within the lake, cannot be invoked to explain the MREE enrichments observed in the lake waters. Copyright (C) 1999 Elsevier Science Ltd.