The bridge between a convecting mantle and tectonic crust: Geodynamics of the mantle lithosphere

对流地幔和构造地壳之间的桥梁：地幔岩石圈的地球动力学

• 批准号: RGPIN-2019-06803
• 负责人: Pysklywec, Russell
• 金额: $ 4.44万
• 依托单位: University of Toronto
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2022
• 资助国家: 加拿大
• 起止时间: 2022-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=751229
• 关键词: bridge; between; convecting; mantle; tectonic

My proposed research will explore the dynamics of the mantle lithosphere as the important bridge zone between the tectonically energetic crust and fluid convecting mantle below. 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. My research program will make tangible advancements in our understanding of this subsurface horizon of the Earth by answering key outstanding questions in three targeted environments where continental mantle lithosphere is/was tectonically active: (1) Do pre-existing "scars" control the tectonic response of the lithosphere?; (2) How and why does mantle lithosphere get completely/partially removed in some regions and what are the consequences at the surface?; (3) What happens when the deep mantle lithosphere collides to form mountains at a tectonic plate boundary zone? The research will explore these questions in tectonically strategic field areas including the plateaus of Anatolia, the Eurekan Orogeny in Canada's high arctic, the Zagros fold-thrust belt in Iran, and the alpine plate boundary zone of the South Island of New Zealand. The research will be carried out by a diverse team made up of undergraduate and graduate students, and a post-doctoral fellow and research associate. We use computational geodynamics for our investigations and the research group is developing advanced new 4-dimensional tools where we consider evolution of the models through time and in three spatial dimensions. In addition, we will be using physical scaled analogue modelling that give us a unique and detailed view of the tectonics from a laboratory benchtop (a significant challenge in studying planetary-scale geodynamics!). As a new and novel application in geosciences we will experiment with approaches in artificial intelligence (AI)-namely, machine learning and neural network techniques to identify governing Earth parameters and classify the Earth's various observed modes of tectonic behaviour. This application of AI to the geosciences is not an established practice, but it is genuine discovery-based research with potential far-reaching impact. The mantle lithosphere is the bridge between the mantle thermal engine and tectonically mobile crust and this research will help reveal what drives global plate tectonics-one of the primary enigmas of our energetic planet. 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.

我提出的研究将探索地幔岩石圈的动力学，作为构造活跃地壳和下方流体对流地幔之间的重要桥梁区域。地幔岩石圈是地球岩石圈的地壳下部分，构成大陆构造板块的最大组成部分。与上面的地壳和下面的流体地幔相比，它的演化研究很少，也知之甚少。我的研究计划将通过回答大陆地幔岩石圈当前/曾经构造活跃的三个目标环境中的关键突出问题，在我们对地球地下地平线的理解方面取得切实进展：（1）预先存在的“疤痕”是否控制着岩石圈的构造响应？ （2）某些地区地幔岩石圈如何以及为何被完全/部分移除，以及对地表的影响是什么？ （3）当深部地幔岩石圈在板块边界带碰撞形成山脉时会发生什么？该研究将在构造战略领域探讨这些问题，包括安纳托利亚高原、加拿大北极地区的尤里卡造山运动、伊朗的扎格罗斯褶皱逆冲带和新西兰南岛的高山板块边界带。 该研究将由一个由本科生和研究生以及博士后和研究员组成的多元化团队进行。我们使用计算地球动力学进行研究，研究小组正在开发先进的新型 4 维工具，我们在其中考虑模型随时间和三个空间维度的演化。此外，我们将使用物理尺度的模拟模型，使我们能够从实验室工作台上获得独特而详细的构造视图（这是研究行星尺度地球动力学的重大挑战！）。作为地球科学中的一种新颖的应用，我们将尝试人工智能（AI）方法，即机器学习和神经网络技术，以识别控制地球参数并对地球的各种观测到的构造行为模式进行分类。人工智能在地球科学中的应用并不是一种既定的做法，但它是真正的基于发现的研究，具有潜在的深远影响。地幔岩石圈是地幔热机和构造运动地壳之间的桥梁，这项研究将有助于揭示驱动全球板块构造的因素——这是我们充满活力的星球的主要谜团之一。此外，作为含金刚石火山金伯利岩管的成因地，研究大陆地幔岩石圈的演化对于了解加拿大矿产工业中重要资源的开发具有直接意义。在更广泛的领域，这项研究将有助于破译金星、火星、木卫一和木卫二等类地体的地质演化，这些类地体与地球相比表现出截然不同的表面构造活动。