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

地球最外面的固体层，称为岩石圈，根据其起源和组成被归类为大陆层或海洋层。大陆岩石圈可以被拉伸，并最终被撕裂，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。与大西洋开放相关的被动边缘是加拿大东部从北极到新斯科舍省的特征，更古老的例子也保存在陆地上。我的研究使用一种高度原创和创新的陆上-近海方法，整合了地质学和地球物理方法，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存中的重要性。根据与裂谷和裂解有关的岩浆活动(熔岩)的体积，被动边缘被分为富岩浆或贫岩浆。加拿大是理想的研究地点，因为这两种情况都会发生。富含岩浆的边缘被认为与高温(例如地幔热柱)和“主动”裂谷作用有关，而富含岩浆的边缘则被认为是由“被动的”远场伸展驱动的。然而，关于地幔热柱和岩浆贫乏边缘上的岩浆作用的证据含糊不清，这表明端元分类过于简单化，因为它没有考虑到构造继承(较老构造的作用)或解释诸如裂谷倾角(非正交伸展)等现象。因此，无论大陆裂谷和裂解是由主动过程还是被动过程驱动的，构造继承、裂谷倾角的作用以及这些机制与裂谷相关岩浆活动的关系尚未解决，将是这一开创性研究计划的重点。这一研究计划的长期目标是通过回答目前尚未解决的问题：被动边缘结构和演化在多大程度上受控于岩浆作用和构造继承，从而促进对大陆裂谷和裂解的驱动和控制的理解。这种创新、综合和全面的方法将涉及对加拿大东部与裂谷有关的变形和岩浆作用进行地质和地球物理测绘，然后进行建模和板块重建。以往的大多数工作要么只研究陆上地区，要么研究近海地区。然而，这里将对陆上和近海地区进行研究，以提供创新的见解，从而取得有影响力的进展。这一影响将通过近海勘探行业的进步实现，他们将受益于更多的海底知识，这将转化为更成功和对环境负责的勘探。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，学术界将受益于对全球构造过程的基本理解的增加。

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.