Assembly, evolution and dynamics of the eastern Canadian Shield: evidence from present-day seismic structure

加拿大东部地盾的组装、演化和动力学：来自当今地震结构的证据

• 批准号: 341802-2013
• 负责人: Darbyshire, Fiona
• 金额: $ 1.97万
• 依托单位: Université du Québec à Montréal
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2019
• 资助国家: 加拿大
• 起止时间: 2019-01-01 至 2020-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=681769
• 关键词: Assembly; evolution; dynamics; eastern; Canadian

Eastern Canada has a rich geologic history, spanning ~4 billion years of tectonic evolution, and likely encompassing the beginning of the plate-tectonic processes of the Earth. Models of present-day crust and upper-mantle structure, in conjunction with studies of surface geology, are key to understanding the forces that shape the continents and the nature of the interactions between the plates and the convecting mantle beneath.My research focuses on understanding the present-day structure and tectonic history of the eastern Canadian Shield. Structural models are derived using data from global earthquakes recorded at broadband seismograph stations across the region, including northern Ontario, Québec, Labrador and the Hudson Bay region. I have played an key role in establishing new seismograph networks across Québec and Labrador, and am also taking an active part in the installation of the US EarthScope Transportable Array in southern Québec.The long-term scientific objectives of the research programme are to investigate the fundamental building blocks of our continent, considering questions such as (i) how does the thickness and nature of the continental upper mantle vary across different tectonic provinces, and is there a correlation between surface geology and deeper structures? (ii) how was the Canadian Shield assembled and what does this tell us about the history of plate tectonics? (iii) how do structural alignments in the mantle relate to past and present continental dynamics? (iv) how do the thick continental keels affect the patterns of flow in the convecting mantle?On the practical side, regional-scale models of upper mantle structure are of increasing interest to the mining industry, especially since diamond formation takes place only under certain mantle conditions. Models of the crust can also be used to refine earthquake locations and thus provide important constraints in seismic hazard research.

加拿大东部拥有丰富的地质历史，跨越约 40 亿年的构造演化，可能涵盖了当今地壳和上地幔结构的模型以及地表研究。地质学是了解塑造大陆的力量以及板块与下方对流地幔之间相互作用的性质的关键。我的研究重点是了解加拿大地盾东部的当今结构和构造历史。结构模型是利用该地区宽带地震台记录的全球地震数据得出的，包括安大略省北部、魁北克、拉布拉多和哈德逊湾地区。我在魁北克和拉布拉多建立新的地震仪网络方面发挥了关键作用。积极参与在魁北克南部安装美国 EarthScope 可移动阵列。该研究计划的长期科学目标是调查我们大陆的基本组成部分，考虑问题例如（i）大陆上地幔的厚度和性质在不同的构造省有何不同，以及地表地质和深层结构之间是否存在相关性？（ii）加拿大地盾是如何形成的，这告诉我们什么？板块构造的历史？（iii）地幔的结构排列与过去和现在的大陆动力学有何关系？（iv）厚大陆龙骨如何影响对流地幔的流动模式？采矿业对上地幔结构的区域尺度模型越来越感兴趣，特别是因为金刚石的形成仅在某些地幔条件下发生，地壳模型也可用于细化地震位置，从而为地震灾害研究提供重要约束。 。