Abstract:
Northern Chile, NW Argentina, and SW Bolivia, (\"the lithium triangle\"), represent a world class reservoir of lithium, but this extraordinary enrichment is still controversial, and different processes have been invoked over the years, including, geothermal waters associated with active volcanism, leaching of soluble salts from volcanic rocks and leaching of lithium-rich clays. The Salar de Atacama (SDA) represents one of the richest reservoirs of Li in northern Chile and has been extensively studied during the past years. Most of the studies have been focused in the southern and southeastern portions, where the highest lithium concentrations have been reported. However, a comprehensive model of water recharge at SDA is still imprecise. We used a combination of isotopic methods, including δ7Li, δ11B and 87Sr/86Sr ratios, with their chemical composition of a set of water samples from salt lakes, geothermal manifestations, groundwaters and surficial diluted waters (rivers and streams with low salinity). This study explores the hydrogeochemical processes controlling the water composition and solute distribution of the SDA. Our data confirm that weathering of the ignimbrites constitutes one of the most important processes in relation of solute origin in the region, where deep water-rock interactions would operate at high temperature, enhancing leaching of Li and other solutes. We determine that groundwater flow entering the SDA has undergone pre-enrichment processes (e.g., leak from Altiplano salt lakes; evaporite dissolution, among others) associated with salt inputs in the Western Cordillera. Our results provide a step forward to a comprehensive understanding of the processes that govern brine formation and lithium enrichment in a hyperarid environment, contributing to a sustainable exploration and exploitation of lithium in these environments.
摘要:
北智利,NW阿根廷,和SW玻利维亚,(“锂三角”),代表世界级的锂储备,但是这种非凡的丰富仍然存在争议,多年来调用了不同的过程,包括,与活火山活动相关的地热水,从火山岩中浸出可溶性盐和浸出富锂粘土。SalardeAtacama(SDA)是智利北部最富有的Li水库之一,在过去几年中得到了广泛的研究。大部分研究集中在南部和东南部,据报道锂浓度最高。然而,SDA补水的综合模型仍然不精确。我们使用了同位素方法的组合,包括δ7Li,δ11B和87Sr/86Sr比率,来自盐湖的一组水样的化学成分,地热表现,地下水和表面稀释水(低盐度的河流和溪流)。这项研究探索了控制SDA的水组成和溶质分布的水文地球化学过程。我们的数据证实,火成岩的风化是该地区溶质起源最重要的过程之一,深水-岩石相互作用将在高温下进行,增强锂和其他溶质的浸出。我们确定进入SDA的地下水流已经经历了预富集过程(例如,高原盐湖泄漏;蒸发岩溶解,除其他外)与西部山脉的盐输入有关。我们的研究结果为全面了解超干旱环境中控制盐水形成和锂富集的过程提供了一步。在这些环境中促进锂的可持续勘探和开发。