Mapping the Archean mantle through the geochemistry of TTG and lamprophyres

通过 TTG 和煌斑岩的地球化学绘制太古代地幔图

• 批准号: 250585-2012
• 负责人: Hollings, Peter
• 金额: $ 2.77万
• 依托单位: Lakehead University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2012
• 资助国家: 加拿大
• 起止时间: 2012-01-01 至 2013-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=507828
• 关键词: Mapping; Archean; mantle; through; geochemistry

This study will investigate the field, geochemical and isotopic characteristics of 2.7 Ga tonalite-trondjhemite-granodiorite (TTG) suites and their major and accessory mineral phases, in several areas of the Superior Province that differ in terms of the thickness of their cratonic roots and histories of upper crustal development. This study of mainly mid- and upper-crustal processes will be linked to contemporaneous events in the lower crust and mantle via a study of crustal and mantle xenoliths in spatially associated late Archean lamprophyres. This will allow us to clarify the formation and stabilization of the world's largest craton, and also provide important insights into the ongoing controversy of granite magma genesis and emplacement processes. In addition combining geochemical and isotopic studies of TTG and lamprophyre hosted xenoliths in well-mapped and geochronologically well-constrained greenstone belts, will allow us to evaluate the nature of Archean tectonic processes and compare them with those of the Phanerozoic. By illustrating the nature of Archean subduction processes and variations in the nature of subcontinental lithospheric mantle, as well as demonstrating correlations between xenolith-overprinting fluids and gold-bearing solutions, this study will make a significant contribution to the debate about the scale and architecture of orogenic gold systems.

本研究将研究优势省几个克拉通根部厚度和上地壳发育历史不同地区的2.7Ga英云闪长岩-奥长花岗闪长岩(TTG)及其主副矿物相(TTG)的野外、地球化学和同位素特征。这项主要研究中、上地壳过程的研究将通过对空间上伴生的晚太古代煌斑岩中的地壳和地幔包体的研究，将与下地壳和地幔的同期事件联系起来。这将使我们能够澄清世界上最大的克拉通的形成和稳定，并为正在进行的花岗岩岩浆成因和侵位过程的争论提供重要的见解。此外，结合地球化学和同位素研究，我们将能够评估太古宙构造作用的性质，并将其与显生宙的构造作用进行比较。通过阐明太古宙俯冲过程的性质和大陆岩石圈地幔性质的变化，以及捕虏体叠加流体与含金溶液之间的相互关系，这项研究将对造山带金矿系统的规模和结构的争论做出重大贡献。