Geodynamics of the continental mantle lithosphere: Investigations into active and ancient evolution of continental plate boundaries and interiors

拟议的研究将调查大陆地幔岩石圈的动力学及其与地壳构造的关系。地幔岩石圈是地球岩石圈的次地壳部分，是大陆构造板块的最大组成部分。与下面的上覆地壳和流体地幔相比，对其演化的研究很少，也了解得很少。该研究计划将在大陆地幔岩石圈正在/曾经在构造活动的三个目标环境中回答重要的悬而未决的问题，从而在我们对地球这一部分的理解方面取得切实的进展：(1)。在某些地区，地幔岩石圈是如何和为什么完全/部分地移走的，对地表有什么影响？(2)当大陆地幔岩石圈在板块边界地带相撞时会发生什么？(3)是什么原因导致了板块变形发生在远离板块边界的“板内”构造事件？这项研究将在构造战略领域探索这些问题，包括加拿大北极高地的尤里坎造山带、新西兰南岛的高山板块边界带、安纳托利亚高原和意大利的亚平宁造山带。 我们使用计算地球动力学进行研究，并正在为这项工作开发先进的新的四维工具，其中我们考虑了模型在时间和三维空间维度上的演变。这些模拟工具与用于全球构造的其他工具不同，因为它们结合了粘塑性流变学、多组分系统和边界条件，从而允许对复杂的地幔-地幔-岩石圈-地壳-表面耦合的热机械勘探。这项研究还将在地球动力学研究中具有创新性和独特性，采用多学科自上而下的方法，将观测约束--地质、地球物理、大地测量--直接纳入计算分析。随着新的地球动力学工具和方法以及有针对性的实地研究，这项研究将在我们对岩石圈动力学和大陆构造如何工作的认识方面取得重大进展。 这项拟议的研究对于探索我们在理解板块构造过程中的一个根本差距--大陆板块如何以及为什么在地质上活跃--具有重要意义。地幔岩石圈是地幔热机和构造活动地壳之间的桥梁，这项研究将有助于揭示是什么驱动了我们活动地球上的板块构造。此外，作为含金刚石火山金伯利岩管的产地，研究大陆地幔岩石圈的演化对了解加拿大矿产行业内重要资源的开发具有直接意义。在更广阔的前沿，这项研究将有助于破译金星、火星、木卫一和欧罗巴等陆地天体的地质演化，这些天体的表面构造活动与地球相比有很大不同。

The proposed research will investigate the dynamics of the continental mantle lithosphere and its relationship to crustal tectonics. The mantle lithosphere is the sub-crustal portion of the Earth’s lithosphere and makes up the largest component member of the continental tectonic plates. Compared to the overlying crust and fluid mantle below, its evolution is little studied and poorly understood. The research program will make tangible advancements in our understanding of this part of the Earth by answering important outstanding questions in three targeted environments where continental mantle lithosphere is/was tectonically active: (1). How and why does mantle lithosphere get completely/partially removal in some regions and what are consequences at the surface?; (2) What happens when continental mantle lithosphere collides at a plate boundary zone?; (3) What causes episodes of “intraplate” tectonics where plate deformation occurs distant from plate boundaries? The research will explore these questions in tectonically strategic field areas including the Eurekan Orogeny in Canada’s high arctic, the alpine plate boundary zone of the South Island of New Zealand, the plateaus of Anatolia, and the Apennine orogen of Italy. We use computational geodynamics for research and are developing advanced new 4-dimensional tools for this work, where we consider evolution of the models through time and in three spatial dimensions. The modelling tools are distinguished from others used for global tectonics as they incorporate viscous-plastic rheologies, multi-component systems, and boundary conditions that allow for the thermomechanical exploration of the complex coupled mantle-mantle lithosphere-crust-surface. The research will also be innovative and distinct among geodynamics studies by using a multidisciplinary top-down methodology where observational constraints--geological, geophysical, geodetic--are integrated directly into the computational analyses. With the new geodynamics tools and methodology and the targeted field studies, the research will make significant progress in our knowledge of lithospheric dynamics and how continental tectonics works. The proposed research is significant for exploring what is a fundamental gap in our understanding of plate tectonic processes—how and why continental plates are geologically active. The mantle lithosphere is the bridge between the mantle thermal engine and tectonically active crust and this research will help reveal what drives plate tectonics on our active Earth. Also, as the site for the genesis of diamond bearing volcanic kimberlite pipes, the study of the evolution of the continental mantle lithosphere has direct implications for understanding the development of important resources within Canada’s mineral industry. Across a broader frontier, the research will help decipher the geologic evolution of terrestrial bodies such as Venus, Mars, Io, and Europa that display much different surface tectonic activity compared to Earth.