Modelling and Interpreting the Surface Evolution of the Earth in Terms of Mantle Convection: Global Implications of High Heat Flow at the Core-Mantle Boundary

根据地幔对流模拟和解释地球表面演化：核-地幔边界高热流的全球影响

• 批准号: 217272-2013
• 负责人: Forte, Alessandro
• 金额: $ 4.15万
• 依托单位: Université du Québec à Montréal
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2013
• 资助国家: 加拿大
• 起止时间: 2013-01-01 至 2014-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=523745
• 关键词: Modelling; Interpreting; Surface; Evolution; Earth

The ultimate goal of this proposal is a fundamental revision of our current understanding of how convection in Earth's mantle works and how this internal dynamics controls the surface geological evolution of the Earth. This admittedly challenging goal is motivated by recent developments from a wide range of fields that point to deficiencies in the current, widespread view that mantle dynamics is dominantly controlled by the subduction of cold lithosphere and hence that Earth's thermal evolution occurs mainly by 'top-down' cooling. New work on seismic tomographic inversions of 3-D mantle structure, incorporating constraints from geodynamics and mineral physics, coupled with very recent mineral physical results on high heat flow at the core-mantle boundary (CMB), and the latest interpretations of Cenozoic plate motions showing the lateral stability of Earth's most active oceanic ridge system (the East Pacific Rise) indicate that the current standard model is, at best, incomplete. There is therefore a pressing need to develop a revised model of mantle convection capable of satisfying the new findings. I therefore propose a program of research involving a 'bottom-up' approach, encompassing the entire depth-extent of the mantle. This work will focus on a number of objectives: (1) Mantle tomography - to significantly improve resolution of the 3-D structures in the lower-mantle below the Pacific Ocean where large-scale upwellings of hot mantle material have been predicted, (2) Thermal evolution - to understand how the evolution of Earth's interior is affected by strong upward heat transport in thermal plumes originating at the CMB, (3) Data assimilation - to obtain high-resolution, accurate reconstructions of thermal structure and mantle flow over the course of the Cenozoic era, and (4) Plate-tectonic evolution - to develop state-of-the-art mantle convection models with complex rheology that yield self-consistent plates dynamically coupled to underlying mantle. One of the most important objectives of this proposal is the training of highly qualified personnel. Their participation will be a key component of this effort to establish a comprehensive new view of the functioning of our planet's internal dynamics.

该提案的最终目标是对我们目前对地幔对流如何运作以及这种内部动力学如何控制地球表面地质演化的理解进行根本性修订。这一公认的具有挑战性的目标是由最近各个领域的发展所推动的，这些发展指出了当前广泛流行的观点的缺陷，即地幔动力学主要由冷岩石圈的俯冲控制，因此地球的热演化主要是通过“自上而下”发生的' 冷却。关于 3-D 地幔结构地震层析反演的新工作，结合了地球动力学和矿物物理学的约束，结合最近关于核-地幔边界 (CMB) 处高热流的矿物物理结果，以及对新生代板块运动的最新解释显示地球最活跃的洋脊系统（东太平洋海隆）的横向稳定性表明，当前的标准模型充其量是不完整的。因此，迫切需要开发一种能够满足新发现的修正的地幔对流模型。因此，我提出了一项涉及“自下而上”方法的研究计划，涵盖地幔的整个深度范围。这项工作将重点关注以下几个目标：(1) 地幔层析成像 - 显着提高太平洋下方下地幔中 3D 结构的分辨率，预测热地幔物质会大规模上涌，(2 ) 热演化 - 了解地球内部的演化如何受到起源于 CMB 的热羽流中强烈向上热传输的影响，(3) 数据同化 - 获得热结构和地幔流的高分辨率、准确重建（4）板块构造演化——开发具有复杂流变学的最先进的地幔对流模型，产生与底层地幔动态耦合的自洽板块。该提案最重要的目标之一是培训高素质人才。他们的参与将成为建立关于地球内部动力运作的全面新观点的努力的关键组成部分。