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

加拿大东部拥有丰富的地质历史，跨越了约40亿年的构造演化，并可能包括地球板块构造过程的开始。现今地壳和上地幔结构的模型，结合地表地质学的研究，是理解塑造大陆的力量以及板块和下面对流地幔之间相互作用的本质的关键。 我的研究重点是了解东加拿大地盾的现今结构和构造历史。结构模型是使用该地区宽带地震仪台站记录的全球地震数据得出的，包括北方安大略、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，并积极参与在魁北克南部安装美国EarthScope移动式阵列。 该研究方案的长期科学目标是调查我们大陆的基本组成部分，同时考虑到以下问题：㈠大陆上地幔的厚度和性质在不同的构造区之间有何不同，地表地质与深层结构之间是否存在关联？(ii)加拿大地盾是如何形成的，这告诉了我们板块构造史的什么？(iii)地幔的结构排列与过去和现在的大陆动力学有什么关系？(iv)厚的大陆龙骨如何影响对流地幔的流动模式？ 在实践方面，上地幔结构的区域尺度模型越来越受到采矿业的关注，特别是因为钻石的形成只发生在一定的地幔条件下。地壳模型也可用于精确地震位置，从而为地震危险性研究提供重要的限制。

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.