Structural and magmatic evolution of rifts and passive margins: implications for continental breakup and natural resources in Canada

地球最外层的固体被称为岩石圈，根据其起源和组成分为大陆层和海洋层。大陆岩石圈可以被拉伸，最终被撕裂，形成一个新的海洋，形成从大陆岩石圈到海洋岩石圈的过渡，称为被动边缘。从北极到新斯科舍省，加拿大东部的被动边缘与大西洋的开放有关，更古老的例子也保存在陆上。使用高度原创和创新的陆上-海上方法整合地质和地球物理方法，我的研究考察了伸展构造过程如何塑造加拿大的地质，以及它们在与加拿大环境和经济需求相关的自然资源的形成和保护中的重要性。根据与裂谷和破裂有关的岩浆活动（熔岩）的体积，被动边缘被划分为岩浆丰富或岩浆贫乏。加拿大是理想的研究地点，因为这两种类型都有。岩浆丰富的边缘被认为与温度升高（例如地幔柱）和“活跃的”裂谷作用有关，而岩浆贫乏的边缘则被认为是由“被动的”远场伸展驱动的。然而，地幔柱和岩浆活动证据的模糊性表明，端元分类过于简单化，因为它无法解释结构继承（旧构造的作用）或解释裂谷倾角（非正交伸展）等现象。因此，大陆的裂谷和破裂是由主动还是被动的过程驱动的，构造继承的作用，裂谷倾角，以及这些机制与裂谷相关岩浆活动的关系都是未解决的，这将是这个开创性研究项目的重点。本研究项目的长期目标是通过回答目前尚未解决的问题：被动边缘构造和演化在多大程度上受岩浆作用和构造继承的控制，从而促进对大陆裂谷和分裂的驱动因素和控制因素的理解？这项创新、综合和全面的方法将包括对加拿大东部与裂谷有关的变形和岩浆活动进行地质和地球物理测绘，然后进行建模和板块重建。大多数以前的工作只研究了陆上或海上区域。然而，在这里，陆上和海上区域都将进行研究，以提供创新的见解，从而带来有影响力的进步。这种影响将通过海上勘探行业的进步来实现，海上勘探行业将受益于水下知识的增强，这将转化为更成功、更环保的勘探。更广泛的加拿大社会也将从这些工业进步中获得经济利益，而学术界也将从对全球构造过程的基本理解的增加中受益。

The solid outermost layer of the Earth, known as the lithosphere, is classified as either continental or oceanic depending on its origin and composition. Continental lithosphere can be stretched and eventually torn apart opening a new ocean creating a transition from continental to oceanic lithosphere called a passive margin. Passive margins related to the opening of the Atlantic Ocean characterize Eastern Canada from the Arctic to Nova Scotia, and older examples are also preserved onshore. Using a highly original and innovative onshore-offshore approach integrating both geological and geophysical methods, my research examines how extensional tectonic processes shaped the geology of Canada, and their importance in the formation and preservation of natural resources that are relevant to Canadian environmental and economic needs. Passive margins are classified as magma-rich or magma-poor, based on the volume of rift- and breakup-related magmatism (molten rock). Canada is the ideal research location as both types occur. Magma-rich margins are postulated to relate to elevated temperatures (e.g. mantle plumes) and `active' rifting, whereas magma-poor margins are suggested to be driven by `passive' far-field extension. However, ambiguity of evidence for mantle plumes and magmatism on magma-poor margins suggests the end-member classification is an oversimplification as it fails to account for structural inheritance (the role of older structures) or explain phenomena such as rift obliquity (non-orthogonal extension). As such, whether continental rifting and breakup is driven by active or passive processes, the role of structural inheritance, rift obliquity, and the relationship of these mechanisms to rift-related magmatism are unresolved and will be the focus of this groundbreaking research program. The long-term goal of this research program is to advance the understanding of the drivers and controls of continental rifting and breakup by answering the presently unresolved question: To what extent is passive margin structure and evolution controlled by magmatism versus structural inheritance? The innovative, integrated, and comprehensive approach will involve geological and geophysical mapping of rift-related deformation and magmatism in Eastern Canada followed by modelling and plate reconstructions. Most previous work studies either only the onshore or the offshore region. Here however, both onshore and offshore regions will be studied to provide an innovative insight and therefore lead to impactful advancements.The impact of this will be realised by advancements in the offshore exploration industry who will benefit from enhanced sub surface knowledge which will translate into more successful and environmentally responsible exploration. Wider Canadian society will also reap economic benefits as a result of these industrial advances, and the academic community will benefit from increases in the fundamental understanding of global tectonic processes.