The role of climate in the accumulation of lithium-rich brine in the Central Andes
The role of climate in the accumulation of lithium-rich brine in the Central Andes
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DOI：
10.1016/j.apgeochem.2013.09.002
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发表时间：
2013-11-01
影响因子：
3.4
通讯作者：
Jordan, T. E.
中科院分区：
文献类型：
--
作者：
Godfrey, L. V.;Chan, L. -H.;Jordan, T. E.
阿根廷西北部安第斯山脉的Salar del Hombre Muerto（SHM）盐池地下富锂卤水的化学和同位素组成与来自以下几个来源的锂一致：现代岩盐饱和泻湖，最近形成的富锂盐和卤水，以及从古盐湖沉淀的岩盐溶解。SHM位于封闭的盆地中，其中包括由Rio los Patos排水的大规模Cerro Galan破火山口的一部分，该破火山口负责90%的地表径流进入salar。这条河的锂同位素组成较低，为千分之3.4，这与地热泉水的重要贡献是一致的。由于水通过火山岩沉积物，覆盖了盆地的大部分排水，锂去除，减少锂/钠，发生，但没有显着的同位素分馏。这表明表面吸附到蒙脱石或水铁矿，而不是锂纳入八面体结构的粘土网站的机制。这些观察结果表明，高海拔沙漠的条件限制了热液泉水的稀释以及粘土矿物的形成，这共同使锂资源迅速积累。在一个多千年的时间尺度上的气候变化，特别是在水文收支，导致溶质积累率已随时间变化，并解耦锂和钠通量。在现代条件下，流入盐湖的水具有高Li/ Na（重量比为7.9 x 10（-3）），三角洲Li-7与基底岩石无法区分（-0.3 ‰至+ 6.4 ‰），而在多雨气候条件下，盐湖的Li/Na比现代泻湖低40倍（0.1-0.3 x 10（-3）与10.6-13.4 x 10（-3）相比），Li-7的增量略高，为+ 6.9 ppm至+ 12.3 ppm，反映了Li-6被吸收为在较潮湿气候下形成的次生矿物。(c)2013爱思唯尔有限公司保留所有权利。
Lithium-rich brine within the sub-surface of the Salar del Hombre Muerto (SHM) salt pan in the Andes of northwestern Argentina has a chemical and isotopic composition which is consistent with Li derived from several sources: the modern halite saturated lagoon, Li-rich salts and brines formed recently, and dissolution of halite which precipitated from ancient saline lakes. SHM lies in the closed basin that includes part of the massive Cerro Galan caldera which is drained by the Rio los Patos, which is responsible for 90% of surface runoff into the salar. The low Li isotope composition, +3.4 parts per thousand, of this river is consistent with significant contributions of geothermal spring water. As water drains through the volcaniclastic deposits which cover a large proportion of the basin, Li removal, as indicated by decreasing Li/Na, occurs but without significant isotope fractionation. This indicates a mechanism of surface sorption onto smectite or ferrihydrite rather than Li incorporation into octahedral structural sites of clays. These observations suggest that conditions in this high altitude desert have limited the dilution of hydrothermal spring water as well as the formation of clay minerals, which jointly have allowed the Li resource to accumulate rapidly. Changes in climate on a multi-millennial time scale, specifically in the hydrologic budget, have resulted in solute accumulation rates that have been variable through time, and decoupled Li and Na fluxes. Inflow to the salar under modern conditions has high Li/ Na (7.9 x 10(-3) by wt) with delta Li-7 indistinguishable from basement rocks (-0.3 parts per thousand to + 6.4 parts per thousand), while under pluvial climate conditions the Li/Na of the saline lake was 40 times lower than the modern lagoon (0.1-0.3 x 10(-3) compared to 10.6-13.4 x 10(-3)) with slightly higher delta Li-7, + 6.9 parts per thousand to + 12.3 parts per thousand, reflecting the uptake of Li-6 into secondary minerals which formed under a wetter climate. (c) 2013 Elsevier Ltd. All rights reserved.