Intrusion-related critical metal deposits throughout the Appalachian orogen: constraining melt fertility and the magmatic-hydrothermal transition

整个阿巴拉契亚造山带与侵入相关的关键金属矿床：限制熔体肥力和岩浆-热液转变

• 批准号: RGPIN-2022-05224
• 负责人: Hanley, Jacob
• 金额: $ 3.72万
• 依托单位: Saint Mary's University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2022
• 资助国家: 加拿大
• 起止时间: 2022-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=755035
• 关键词: Intrusion; related; critical; metal; deposits

The eastern margin of Canada is comprised of geological terranes that were "accreted" (material added to the side of a tectonic plate) during mountain building events (the Appalachian Orogeny) beginning more than 480 million years ago. These terranes contain igneous intrusions formed mainly by melting of the crust during accretion. Some of these intrusions host deposits of metals (e.g., tin, tungsten, lithium, cesium, indium, rare-earth elements) that are critical for Canada's continuing transition to a low-carbon, digitized economy. In Nova Scotia and New Brunswick, past research on intrusion-related deposits has historically focused on using bulk (the whole rock) methods of chemical and isotopic analyses to constrain the metal "fertility" of magmas (the likelihood that magmas of specific ages and compositions could form metal deposits). However, information yielded from bulk analyses is often ambiguous because bulk igneous rocks are end-products of multiple geological processes that can erase, or diminish, the original chemical signature of magmas and related fluids at different stages in their evolution. Consequently, current geological models for intrusion-related deposits in the Appalachian orogen require revision. The analysis of melt and fluid inclusions (microscopic samples of formerly molten rock and hydrothermal solutions that transported and concentrated metals, trapped in minerals throughout geological time) is the most robust approach to directly measure the metal content of ancient magmas and related volatiles. The proposed research program will constrain the evolution of variably mineralized igneous rocks in the Appalachian Orogeny through the investigation of melt and fluid inclusions. These inclusions, trapped in relatively physically and chemically robust minerals (e.g., zircon) will be analyzed using a variety of microanalytical methods. Individual projects will advance overall research program objectives by investigating the magmatic history of igneous settings of different ages and varying metal endowments. The objective will be to better understand the relative importance of primary controls (e.g., the magma source composition, crystallization, contamination, fluid degassing) on magma metal endowment and economic potential. Trainees involved in the proposed research will gain valuable skills and knowledge that will be transferable to careers in academia, government and the private sector and generate a range of data products and new knowledge suitable for a variety of end-users. The program will provide important updates to metallogenic models not only in the study areas, but in other similar terranes globally, and more broadly, will address fundamental questions about magmatic processes in the Appalachian orogen, testing the validity of previous studies. The research proposed has clear application to the natural resource field, aiming to provide exploration criteria that will have socio-economic benefit to Canada.

加拿大的东边边缘由在4.8亿年前开始的山区建筑事件（阿巴拉契亚造山心）中“积聚”的地质地层（添加到构造板的侧面）。这些地层包含火成岩的侵入，主要是通过堆积过程中地壳熔化而形成的。其中一些侵入物中有金属的沉积物（例如锡，钨，锂，剖宫产，im依，稀土元素），这对于加拿大持续过渡到低碳，数字化经济至关重要。在新斯科舍省和新不伦瑞克省，过去对入侵相关的沉积物的研究历史上一直集中在使用散装（整个岩石）化学和同位素分析方法来限制岩浆的金属“生育力”（特定年龄和成分的岩浆可能形成金属沉积物的可能性）。然而，从批量分析中产生的信息通常是模棱两可的，因为大量火成岩是多种地质过程的最终产物，可以消除或减少岩浆的原始化学特征和相关流体在其进化中的不同阶段。因此，阿巴拉契亚造山基因中与入侵相关沉积物的当前地质模型需要修订。对熔体和流体夹杂物的分析（在整个地质时期被困在矿物质中的熔融和浓缩金属的以前熔融岩石和水热溶液的微观样品）是直接测量古代岩浆和相关挥发物的金属含量的最强大方法。 拟议的研究计划将通过研究融化和液体包含物来限制阿巴拉契亚造山基因中矿化的火成岩的变化。这些夹杂物将使用多种微分析方法分析，被困在相对和化学上可靠的矿物质（例如锆石）中。各个项目将通过研究不同年龄和不同金属捐赠的火成岩环境的岩浆历史来推动整体研究计划目标。目的是更好地了解主要控制（例如，岩浆源组成，结晶，污染，流体脱气）对岩浆金属赋和经济潜力的相对重要性。参与拟议研究的学员将获得有价值的技能和知识，这些技能和知识将可以转移到学术界，政府和私营部门的职业，并生成一系列数据产品和适合各种最终用户的新知识。该计划将不仅在研究领域，而且在全球其他类似的地形中，更广泛地为金属源性模型提供重要的更新，将解决有关阿巴拉契亚造山基因中岩浆过程的基本问题，以测试先前研究的有效性。拟议的研究对自然资源领域有明确的应用，旨在提供对加拿大有社会经济利益的勘探标准。