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: 2017
• 资助国家: 加拿大
• 起止时间: 2017-01-01 至 2018-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=633739
• 关键词: Metallogeny; convergent; collisional; plate; margins

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.

会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。该提案的目的是汇集和扩大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学，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;罕见的前寒武纪斑岩矿床，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学的影响。