Mafic Layered Intrusions Through Time

随着时间的推移，镁铁质层状侵入

• 批准号: 249474-2013
• 负责人: Scoates, James
• 金额: $ 2.91万
• 依托单位: University of British Columbia
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2015
• 资助国家: 加拿大
• 起止时间: 2015-01-01 至 2016-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=570620
• 关键词: Mafic; Layered; Intrusions; Through; Time

Mafic layered intrusions crystallize from basaltic magma to form large bodies of igneous rocks that exhibit prominent layering, preserving stunning rock records of the processes by which magma evolves within the Earth's crust. These intrusions contain world-class deposits of chromium (Cr), platinum group elements (PGE), and vanadium (V), metals that are vital to industry and society in general. Despite their scientific and practical importance, precise age constraints are lacking and many aspects of their origin and formation are still poorly known. The proposed research aims to fill these critical knowledge gaps and will take advantage of recent analytical developments and state-of-the-art instrumentation to constrain the age, duration, and cooling of mafic layered intrusions. This will be achieved by detailed fieldwork and geochemical analysis of rocks and minerals from some of the world's largest and most influential layered intrusions that collectively represent a significant span of Earth history (over 2.5 billion years): (1) the Stillwater Complex, the exposed fragment of a large layered intrusion in the Beartooth Range of the Wyoming Archean Province, including the PGE-rich J-M Reef, (2) the Bushveld Complex, the world's largest layered intrusion, located in the northern Kaapvaal craton of South Africa, and host to some of the richest Cr-PGE-V ore deposits on Earth, (3) the Great Dyke, a 550 km-long layered intrusion in the Zimbabwe craton of southern Africa, containing the world's second largest reserve of PGE, (4) the Kiglapait Intrusion, a bowl-shaped intrusion exposed in the Nain Plutonic Suite of coastal Labrador, and (5) the Skaergaard Intrusion of eastern Greenland, one of the most remarkable layered igneous bodies on Earth that is related to thick sequences of continental flood basalts and opening of the North Atlantic Ocean. The proposed research will yield new scientific insights on timescales of magmatic processes and cooling for these striking rocks, challenging presently known basic concepts of magma crystallization and evolution. The results of this work will have direct implications for the origin of magmatic ore deposits and can be applied to the investigation of less well-studied intrusions in Canada and worldwide.

基性层状侵入物由玄武岩岩浆结晶而成，形成巨大的火成岩体，呈现出明显的分层，保存了地壳内岩浆演化过程的惊人岩石记录。这些侵入体含有世界级的铬（Cr）、铂族元素（PGE）和钒(V)矿床，这些金属对工业和社会至关重要。尽管它们在科学上和实践上都很重要，但缺乏精确的年龄限制，而且它们的起源和形成的许多方面仍然鲜为人知。该研究旨在填补这些关键的知识空白，并将利用最新的分析发展和最先进的仪器来限制基性层状侵入体的年龄、持续时间和冷却。这将通过对一些世界上最大和最具影响力的层状侵入体的岩石和矿物进行详细的实地调查和地球化学分析来实现，这些侵入体共同代表了地球历史的重要跨度（超过25亿年）：(1)静止水杂岩（Stillwater Complex），这是怀俄明州太古代省Beartooth山脉的一个大型层状侵入体的暴露片段，包括富含pge的J-M礁；(2)Bushveld杂岩（Bushveld Complex），这是世界上最大的层状侵入体，位于南非Kaapvaal克拉通北部，拥有地球上最丰富的Cr-PGE-V矿床；(3)Great Dyke，位于非洲南部津巴布韦克拉通的一个550公里长的层状侵入体。包含世界第二大PGE储备，(4)Kiglapait侵入岩，一个暴露在拉布拉多沿海的Nain Plutonic套件中的碗状侵入岩，以及(5)格陵兰东部的Skaergaard侵入岩，地球上最显著的分层火成岩之一，与大陆洪水玄武岩的厚层序列和北大西洋的开放有关。提出的研究将对岩浆过程的时间尺度和这些撞击岩石的冷却产生新的科学见解，挑战目前已知的岩浆结晶和演化的基本概念。这项工作的结果将对岩浆矿床的起源产生直接影响，并可应用于加拿大和世界范围内研究较少的侵入体的调查。