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，结合表面地质学的研究，是理解形成大陆的力量和板块与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加拿大东部地盾的现代结构和构造历史。结构模型是利用该地区宽带地震台站记录的全球地震数据得出的，该地区包括安大略省北部、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，还积极参与了在魁北克南部安装美国地球望远镜可移动阵列的工作。该研究计划的长期科学目标是调查我们大陆的基本构造块，考虑以下问题：(I)大陆上地幔的厚度和性质在不同的构造省份之间是如何变化的，以及表面地质和深层结构之间是否存在相关性？(Ii)加拿大盾是如何组装的，这对板块构造的历史有什么启示？(3)地幔中的构造排列与过去和现在的大陆动力学有何关系？(4)厚的大陆龙骨如何影响对流地幔中的流动模式？在实际方面，上地幔结构的区域尺度模型越来越引起采矿业的兴趣，特别是因为钻石的形成只在特定的地幔条件下发生。地壳模型也可用于精确定位地震位置，从而在地震危险性研究中提供重要约束。

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.