Petrogenetic investigation of Neoarchean anorthosite-greenstone associations in the Superior Province, Canada

加拿大苏必利尔省新太古代斜长岩-绿岩组合的岩石成因研究

• 批准号: 250926-2013
• 负责人: Polat, Ali
• 金额: $ 1.97万
• 依托单位: University of Windsor
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2013
• 资助国家: 加拿大
• 起止时间: 2013-01-01 至 2014-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=525074
• 关键词: Petrogenetic; investigation; Neoarchean; anorthosite; greenstone

The geological models proposed to explain the origin of Archean anorthosite-greenstone associations in the Superior Province of Canada require re-evaluation within the context of new high-precision geochemical data. Over the next five years I plan to study the field, microscopic and geochemical characteristics of Archean anorthosite-greenstone associations in the Superior Province, to constrain their petrogenesis and geodynamic setting. The anorthosite-greenstone associations to be studied include the Neoarchean Bad Vermilion Lake (Ontario) and Doré Lake (Quebec) complexes. I will systematically sample each lithological unit in these associations and analyze them for major and trace elements and isotopes (Nd, Pb, O), to improve our understanding the petrogenetic origin of these rocks. The geochemical characteristics of each rock type in the anorthosite complexes and spatially associated volcanic rocks are expected to reflect petrological processes responsible for the compositional and isotopic variations in these rocks and their sources. Trace elements and Nd, Pb and O isotopes are sensitive to petrogenetic processes and can be used to distinguish between different petrogenetic processes. These petrological processes can then be linked to the regional scale Neoarchean geodynamic processes in the Superior Province. Two hypotheses will be tested: (1) anorthosite-greenstone associations are genetically related and represent relict Archean oceanic crust; and (2) they are petrogenetically unrelated and do not represent Archean oceanic crust. The results of this project will have the following significance: (1) enhance our knowledge on the petrogenetic origin of Archean layered anorthosites and associated mafic to ultramafic intrusive rocks; and (2) the Canadian resource industry will benefit from this research program given that anorthosites and associated ultramafic rocks have high potential for chromite, vanadium, copper, nickel, and PGE (Platinum Group Elements) mineral deposits.

为解释加拿大上级省太古代斜长岩-绿岩组合的起源而提出的地质模型需要在新的高精度地球化学数据的范围内重新评价。在未来的五年里，我计划研究的领域，微观和地球化学特征的太古代斜长岩-绿岩组合在上级省，以限制其岩石成因和地球动力学背景。待研究的斜长岩-绿岩组合包括新太古代的巴特朱红湖（安大略）和多雷湖（魁北克）复合体。我将系统地对这些组合中的每个岩性单元进行采样，并分析它们的主要和微量元素以及同位素（Nd，Pb，O），以提高我们对这些岩石的成岩起源的理解。斜长岩杂岩和空间相关火山岩中每种岩石类型的地球化学特征，预计将反映岩石学过程中负责这些岩石及其来源的成分和同位素的变化。微量元素和Nd、Pb、O同位素对成岩作用敏感，可用于区分不同的成岩作用。这些岩石学过程，然后可以连接到区域规模的新太古代地球动力学过程中的上级省。将检验两个假设：（1）斜长岩-绿岩组合在成因上相关，代表太古代残留洋壳;（2）它们在岩石成因上无关，不代表太古代洋壳。本课题的研究成果具有以下意义：（1）加深了对太古代层状斜长岩及相关镁铁质-超镁铁质侵入岩成因的认识;以及（2）鉴于斜长岩和相关的超镁铁岩具有很高的铬铁矿、钒、铜、镍，和铂族元素矿床。