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: 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=570927
• 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.

本研究将调查的字段，地球化学和同位素特征的2.7 Ga英云闪长岩-奥辉闪长岩-花岗闪长岩（TTG）套件和它们的主要和辅助矿物相，在几个地区的上级省，不同的厚度方面的英云闪长岩根和上地壳发展的历史。这一研究主要是中地壳和上地壳的过程，将通过研究空间相关的晚太古代层积岩中的地壳和地幔捕虏体，与下地壳和地幔中的同生事件联系起来。这将使我们能够澄清世界上最大的克拉通的形成和稳定，也提供了重要的见解，花岗岩岩浆成因和侵位过程的持续争议。此外，结合地球化学和同位素研究的TTG和Lamberre托管捕虏体在良好的映射和地质年代学约束的绿岩带，将使我们能够评估太古代构造过程的性质，并将它们与古生代的。通过阐明太古代俯冲过程的性质和大陆岩石圈地幔性质的变化，以及证明捕虏体叠印流体和含金溶液之间的相关性，这项研究将对有关造山带金矿系统的规模和结构的争论做出重大贡献。