Magmatic assemblages and metasomatic overprints

岩浆组合和交代叠印

• 批准号: 7721-2007
• 负责人: Martin, RobertFrancois
• 金额: $ 2.68万
• 依托单位: McGill University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2009
• 资助国家: 加拿大
• 起止时间: 2009-01-01 至 2010-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=420460
• 关键词: Magmatic; assemblages; metasomatic; overprints

In broad terms, I focus on the mineralogy and petrology of crustal rocks, in particular those rocks formed in an extensional tectonic environment. I document what the magma produced, and how an aqueous phase exsolved from the melt or from outside interacts with the just-formed hot rocks as they cool and contract. Evolved igneous rocks like granites, nepheline syenites and carbonatites commonly involve a mixed crust + mantle provenance, which can best be evaluated using isotope geochemistry. The hydrothermal mobility of high-field-strength elements like Ta, Zr and Ti remains a contested area, and requires much more documentation in field-based studies. More basic rocks also bear the hydrothermal imprints, and mobility in those cases may well involve the platinum-group elements, of great economic importance. Field studies will focus on the Bancroft area of Ontario, the classic anorogenic Younger Granites of Nigeria, the granitic pegmatites of the Borborema Province, Brazil, and of Catalunya, Spain, the catazonal rocks of southern Madagascar, and the alkaline rocks of the Monteregian Province of Quebec. The crust also bears the imprint of localized impact-generated melting; a project on the Clearwater Lake craters in northern Quebec will shed light on the remelting of the metamorphic Archean basement and the limestone cover in the area. Many of the research projects address topics at the "cutting edge", about processes that shaped of crust of the Earth. At the same time, they touch on economic aspects, in particular those studies that address the platinum-group elements and the high field-strength elements, and thus have the potential of an impact on the optimization of mineral exploration for those commodities in Canada and elsewhere.

从广义上讲，我的重点是地壳岩石的矿物学和岩石学，特别是那些形成于伸展构造环境中的岩石。我记录了岩浆产生了什么，以及当刚形成的热岩冷却和收缩时，从熔体中析出的水相或从外部出来的水相如何与刚刚形成的热岩相互作用。演化的火成岩，如花岗岩、霞石正长岩和碳酸盐岩，通常涉及地壳+地幔混合物源，这可以用同位素地球化学来评估。Ta、Zr和Ti等高场强元素的热液迁移性仍然是一个有争议的领域，需要更多的实地研究文献。更多的基性岩也带有热液印迹，在这些情况下，流动性很可能涉及具有重大经济意义的铂族元素。实地研究将集中在安大略省的班克罗夫特地区、尼日利亚典型的非造山年轻花岗岩、巴西博尔博雷马省和西班牙加泰罗尼亚的花岗伟晶岩、马达加斯加南部的卡特罗特岩石和魁北克蒙特雷吉亚省的碱性岩石。地壳还带有局部撞击产生的熔融的印记；魁北克北部清水湖陨石坑的一个项目将揭示该地区太古宙变质基底和石灰岩盖层的重熔情况。许多研究项目都涉及“前沿”课题，即形成地壳的过程。同时，它们涉及经济方面，特别是涉及铂族元素和高场强元素的研究，因此有可能对加拿大和其他地方对这些商品的矿物勘探的最优化产生影响。