Metallogeny of convergent and collisional plate margins through geological time

地质时期汇聚和碰撞板块边缘的成矿作用

• 批准号: RGPIN-2017-05082
• 负责人: Richards, Jeremy
• 金额: $ 2.33万
• 依托单位: Laurentian University of Sudbury
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2018
• 资助国家: 加拿大
• 起止时间: 2018-01-01 至 2019-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=663325
• 关键词: Metallogeny; convergent; collisional; plate; margins

Metallogeny of convergent and collisional plate margins through geological time:***Convergent and collisional tectonic plate margins, where one plate subducts beneath or collides with another, are the only locations where crustal materials are returned to the mantle. These materials include volatiles such as water, sulfur, and chlorine, which are critical for the solubilization and transport of metals in mantle-derived magmas, and which are exsolved again as hydrothermal fluids from those magmas upon emplacement in the upper crust. Porphyry Cu±Mo±Au and epithermal Au±Cu ore deposits are formed where the flow of these fluids is sufficiently focused and voluminous to result in precipitation of ore minerals in economic concentrations. While major advances have been made in recent years relating to ore depositional processes, the underlying magmatic and tectonic processes that give rise to “fertile” magmas (i.e., magmas with the potential to form ore deposits) are less well understood, and less well integrated into metallogenic models. The objective of this proposal is to draw together and extend research on subduction and collision zone tectonics and magmatism, with a focus on constraining the processes that affect the behaviour of metals. This is a large endeavour, and I will work collaboratively with other researchers with specialist expertise to achieve these goals. Specific areas of research will be: Phanerozoic subduction and post-subduction ore-forming processes at an Earth-system scale; the metallogeny of the lower crustal roots of magmatic arcs, where evidence for deep processing of mantle-derived metals can be observed in rare exposures; and rare Precambrian porphyry deposits that may preserve evidence of changing tectonomagmatic processes over geological time, and their effects on metallogeny.******This research has significance for the exploration and discovery of new resources of Cu, Mo, Au, and other metals, which are critical for the maintenance and growth of modern society. Discovery rates of economic deposits of these metals are falling despite increased exploration expenditures, and the industry is looking for new concepts and better models that can help predict the occurrence of ore deposits, especially in previously overlooked or covered terranes. The regional scope of the proposed research provides fundamental information about the prospectivity of magmas and volcanic arcs, which can be used to develop novel exploration strategies in mature mineral belts, and to prioritize and focus exploration in new regions. Parallel research (not part of this proposal) takes this a step further to also consider the environmental and socioeconomic impacts of mining.

汇聚和碰撞板块边缘在地质时期的成矿作用：* 汇聚和碰撞构造板块边缘，一个板块俯冲到另一个板块之下或与另一个板块碰撞，是地壳物质返回地幔的唯一位置。这些物质包括挥发性物质，如水、硫和氯，这些物质对幔源岩浆中金属的溶解和迁移至关重要，并且在上地壳就位时再次作为热液流体从这些岩浆中出溶。斑岩型Cu±Mo±Au矿床和浅成低温热液型Au±Cu矿床是在这些流体的流动足够集中和体积大，导致矿石矿物以经济浓度沉淀的地方形成的。虽然近年来在矿石沉积过程方面取得了重大进展，但产生“肥沃”岩浆的底层岩浆和构造过程（即，具有形成矿床潜力的岩浆）的认识较少，也未很好地纳入成矿模型。该提案的目标是汇集并扩展对俯冲和碰撞带构造和岩浆活动的研究，重点是限制影响金属行为的过程。这是一项巨大的努力，我将与其他具有专业知识的研究人员合作，以实现这些目标。具体的研究领域将是：地球系统规模的中生代俯冲和俯冲后成矿过程;岩浆弧下地壳根部的成矿作用，在那里可以在罕见的暴露中观察到幔源金属深加工的证据;以及罕见的前寒武纪斑岩矿床，它可能保存地质时期不断变化的构造岩浆过程的证据及其对成矿作用的影响。这一研究对于探索和发现铜、钼、Au等金属新资源具有重要意义，这些金属对现代社会的维持和发展至关重要。尽管勘探支出增加，但这些金属的经济矿床的发现率正在下降，该行业正在寻找新的概念和更好的模型，以帮助预测矿床的出现，特别是在以前被忽视或覆盖的矿床中。拟议研究的区域范围提供了有关岩浆和火山弧前景的基本信息，可用于在成熟矿带制定新的勘探战略，并优先考虑和重点勘探新区域。并行研究（不属于本提案的一部分）进一步考虑采矿的环境和社会经济影响。