Collaborative Research: As above so below: Quantifying the role of simultaneous LLSVPs and continents on Earth's cooling history using numerical simulations of mantle convection

合作研究：如上所述，如下：使用地幔对流数值模拟来量化同时发生的 LLSVP 和大陆对地球冷却历史的作用

• 批准号: 2310325
• 负责人: Catherine Cooper
• 金额: $ 17.34万
• 依托单位: Washington State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-07-01 至 2026-06-30
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2310325&HistoricalAwards=false
• 关键词: Collaborative; Research; above; so; below

Earth’s cooling rate affects many processes necessary for a dynamic, living world, from plate tectonics to generation of the planet’s magnetic field. Understanding the establishment, evolution, and continued functioning of such processes requires knowledge of the planet’s thermal history, but much of that history remains unconstrained in part because several controlling mechanisms have yet to be quantified. As such, this award aims to study how Earth’s cooling rate may be altered through variable insulation of the planet’s interior by continents along the surface and large, continent-sized piles of anomalous material (Large Low Shear Velocity Provinces; LLSVPs) covering portions of the outer core. Previous studies separately examined the insulating effects of continents and LLSVPs, but none focused on the potentially counteracting effects of simultaneous insulating bodies: continents are predicted to increase the mantle’s internal temperature while LLSVPs decrease it. This study will quantify the resulting dynamic and thermal effects of such bodies and the implications for the Earth’s cooling history, plate tectonics, and magnetic field. Furthermore, both continents and LLSVPs act as chemical reservoirs that isolate critical elements from participating in global cycling for potentially long portions of Earth’s history. However, the formation and evolution of LLSVPs is still actively debated. This study will identify their likely thermal and chemical fingerprints as an additional means of testing their potential formation timing and duration. In addition to scientific advances, this project will expand educational opportunities centered on the deep Earth through an interdisciplinary game development program that will produce a new, widely distributed, educationally focused video game designed to combat several geoscience misconceptions while supporting a diverse, interdisciplinary group of ten undergraduate student developers. Finally, this award supports two graduate students and a post-doctoral scholar at two rural, land-grant universities, Washington State University and University of Idaho. This award supports a novel study that will systematically evaluate how simultaneous surface and basal insulating bodies in Earth’s mantle (continents + LLSVPs) jointly alter the thermal evolution and internal mantle dynamics of the Earth. Two-dimensional spherical numerical simulations will be used to quantify the impacts of simulated LLSVP and continental materials in models of increasing rheological, thermal, and temporal complexity to address three research objectives: (1) isolate the fundamental processes governing interactions of surface (continent) and basal (LLSVP) insulators, (2) quantify the influence of complex rheology and internal heating on the basal and surface insulator convective system, and (3) examine impacts of time-evolving basal and surface insulators through Earth’s history. Numerical simulations of the Earth’s mantle subject to surface (continent) and basal (LLSVP) insulators will be conducted using the highly parallel finite-element code ASPECT (Advanced Solver for Problems in Earth’s ConvecTion). Simulations will be solved in parallel across ~32-256 computational cores on University of Idaho’s Falcon supercomputer (33k cores, 1.17 Petaflop) or Washington State University’s Kamiak high performance computer cluster. For each of the ~200 planned simulations, the conservation equations will be discretized across a dynamically refined grid of ~2 million finite elements with enhanced element resolution near strong thermal and compositional gradients, allowing an accurate quantification of heat transfer through the model system.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

地球的冷却速率会影响一个动态，生活世界所必需的许多过程，从板块构造到生成地球的磁场。了解此类过程的建立，演变和持续运作需要了解地球的热历史，但是大部分历史仍然不受限制，部分原因是尚未量化几种控制机制。因此，该奖项旨在通过沿地面的延伸以及覆盖外部芯的部分的反常物质（大型低剪切速度省； LLSVPS）的隔热以及持续较大的尺寸的异常材料（大型低剪切速度省； LLSVPS）来研究地球的冷却速率如何改变地球的冷却速率。先前的研究分别研究了连续和LLSVP的绝缘作用，但没有一个集中于同时绝缘体的潜在抵消效应：预计持续会增加地幔的内部温度，而LLSVP会降低它。这项研究将量化此类物体的产生动态和热效应，以及对地球冷却历史，板块构造和磁场的影响。此外，大陆和LLSVP都充当化学储层，这些储层将关键要素与参与全球骑自行车的参与中潜在地球历史的潜在较长部分。但是，LLSVP的形成和演变仍在积极争论中。这项研究将确定其可能的热和化学指纹是测试其潜在形成时间和持续时间的另一种手段。除了科学进步外，该项目还将通过一个跨学科的游戏开发计划扩大以深层为中心的教育机会，该计划将生产出一种新的，广泛的分布，以教育为中心的视频游戏，旨在抵抗几个地球科学失误，同时支持多样性，跨学科，由十个本科生开发人员组成的跨学科小组。最后，该奖项支持两名研究生和一名博士后科学，在两所农村，土地授予大学，华盛顿州立大学和爱达荷大学。该奖项支持一项新的研究，该研究将系统地评估地球地幔（大陆 + LLSVP）中同时表面和基本绝缘体如何共同改变地球的热进化和内部地幔动力学。二维球形数值模拟将用于量化越来越多的llsvp和大陆材料在增加流变，热和临时复杂性模型中的影响，以解决三个研究目标：（1）隔离表面（陆上）和基础（llsvp）的基本相互作用的基本过程（隔离基础）的基本互动，（llsvp）的影响及其影响量，（2）插入量及其影响（2）互助及其影响及其影响及其影响及其影响。绝缘体对流系统，以及（3）通过地球历史上的碱性和表面绝缘体的检查影响。将使用高度平行的有限元代码方面（对于地球对流中的问题）进行地面（大陆）和基本（LLSVP）绝缘体的数值模拟。在爱达荷大学的猎鹰超级计算机（33k核心，1.17 PETAFLOP）或华盛顿州立大学的Kamiak高性能计算机集群上，将在〜32-256的计算核心上并联求解。对于约200个计划的模拟中的每一个，将在约200万个有限元素的动态精制网格中离散，并在强大的热热和复合梯度附近分辨率提高了元素分辨率，从而可以通过模型系统准确地量化热传输。该奖项反映了NSF的法定任务，并通过评估了范围的范围，并通过评估了范围的范围。