Modelling the genesis of the Separation Rapids petalite-lepidolite pegmatites as a guide to their exploration

模拟分离急流的透锂长岩-锂云母伟晶岩的成因，作为其勘探的指南

• 批准号: 518969-2017
• 负责人: WilliamsJones, Anthony
• 金额: $ 2.14万
• 依托单位: McGill University
• 依托单位国家: 加拿大
• 项目类别: Collaborative Research and Development Grants
• 财政年份: 2020
• 资助国家: 加拿大
• 起止时间: 2020-01-01 至 2021-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=696418
• 关键词: Modelling; genesis; Separation; Rapids; petalite

Lithium is in very high demand because of concerns about global warming and government decisions to replace gasoline and diesel vehicles with electric vehicles powered by lithium-ion batteries. This demand also strongly affects other applications requiring lithium, notably in the ceramic/glass industry. A lithium mineral that is particularly sought by the ceramics and glass industry is petalite, because of its high capacity to reduce thermal shock. Significantly, in the Separation Rapids pegmatites, Ontario, Canada has one of the largest petalite resources in the World plus large resources of lepidolite, another important lithium mineral. The research described in this proposal is designed to investigate the nature, distribution and origin of these petalite-rich pegmatites as part of an overall objective to determine their genesis and develop tools that will be important to their successful exploration. The pegmatites belong to the LCT (Lithium-Cesium-Tantalum) class of pegmatites, for which there is no consensus on genesis. Two hypotheses currently dominate our view of their origin, the water-saturated magma hypothesis of Jahns and Burnham (1969) and the water-undersaturated hypothesis of London (1992). According to the former hypothesis, pegmatitic textures result from saturation of the magma with water, which lowers viscosity and suppresses nucleation, whereas for the latter hypothesis, they are explained by crystallisation from a boundary layer liquid enriched in network modifier elements (B, P and F) that reduce the viscosity. For both models, mineral chemistry, in predicting magma evolution, will provide tools for targeting lithium-rich pegmatites. If the Jahns and Burnham (1969) model is correct, then hydrothermal fluids would have affected the host rocks, and their lithogeochemistry could be used to develop vectors towards lithium-rich pegmatites. In this project, we will make use of a combination of petrographic, mineral chemical, isotopic, melt/fluid inclusion, and thermodynamic analyses to develop a robust genetic model for the Separation Rapids pegmatite field. The study will shed new light on the origin of a poorly understood strategic class of mineral deposits and, identify new guidelines for their exploration.

锂的需求很高，因为人们担心全球变暖和政府决定用锂离子电池供电的电动汽车代替汽油和柴油车。这种需求也强烈影响需要锂的其他应用，特别是在陶瓷/玻璃行业中。陶瓷和玻璃工业特别寻求的锂矿物质是花瓣的，因为它具有降低热冲击的高能力。值得注意的是，在分离急流pegmatites中，加拿大安大略省是世界上最大的花瓣资源之一，还有大量鳞甲米属矿物质，另一种重要的锂矿物质。本提案中描述的研究旨在研究这些富含花瓣岩石的pegmatites的性质，分布和起源，这是确定其起源和开发工具的总体目标的一部分，这些工具对他们的成功探索很重要。 pegmatites属于pegmatites的LCT（锂tantalum锂）类别，为此，对创世纪没有共识。目前有两个假设主导着我们对它们的起源的看法，即Jahns和Burnham（1969）的水饱和岩浆假说以及伦敦的水不饱和假设（1992）。根据前者的假设，质质质地是由水用水饱和而导致的，从而降低了粘度并抑制成核，而对于后一种假设，它们是由从网络修饰元素中富集的边界层液体（b，p和f）的结晶来解释的（b，p和f），从而降低了粘度。对于这两种模型，矿物化学在预测岩浆演化时都将提供靶向富含锂岩石岩石的工具。如果Jahns and Burnham（1969）模型是正确的，那么水热流体将影响宿主岩石，并且它们的岩性化学可用于开发向量朝向富含锂的pegmatites。在这个项目中，我们将利用岩石学，矿物质化学，同位素，融化/流体包含和热力学分析的组合，为分离急流pegmatite场开发可靠的遗传模型。这项研究将为矿藏的战略性矿藏阶层不足，并确定其探索的新准则的新启示。