Thermal evolution of the Earth: the modes of mantle convection in the Precambrian

地球的热演化：前寒武纪地幔对流模式

基本信息

批准号：
1753916
负责人：
Jun Korenaga
金额：
$ 34.61万
依托单位：
Yale University
依托单位国家：
美国
项目类别：
Continuing Grant
财政年份：
2018
资助国家：
美国
起止时间：
2018-03-15 至 2022-08-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=1753916&HistoricalAwards=false
关键词：
Thermal evolution Earth modes mantle

项目摘要

Plate tectonics is a special class of mantle convection, being observed only on Earth among terrestrial planets in our solar system. It is responsible for a vast array of geological processes, from the generation of continental crust to the modulation of atmospheric composition. Yet, some fundamental questions about its history remain unresolved: when plate tectonics began on Earth and how it has evolved through time. This project aims to resolve the likely mode of mantle convection in the Precambrian (i.e., after the solidification of the putative magma ocean in the early Earth to the beginning of the Phanerozoic at 540 million years ago), by building a robust theoretical framework and exploring its implications for geological and geochemical observations. Reconstructing the evolutionary path of plate tectonics on Earth is one of the most fundamental geophysical problems, providing a global context for geological, geophysical, and geochemical processes, and the radius of the potential impact of this research would cover nearly all branches of solid Earth sciences. Expected research results should also find their applications in the physics and chemistry of terrestrial planets at large and are expected to become part of the theory of habitable planets. This project will provide support and training for a postdoctoral associate and a graduate student, as well as summer intern or thesis projects for undergraduates. The planned research has the following five major objectives: (1) Establishing a regime diagram of mantle convection as a function of internal Rayleigh number, the temperature dependency of viscosity, yielding criteria, and the internal heating ratio, so that we can estimate how the mode of convection has evolved in the past, (2) quantifying the relation between quasi-steady-state solutions and transient situations, in terms of the mode of convection and heat-flow scaling, so that we can analyze collectively different numerical approaches to the evolving mantle dynamics in a unifying fashion, (3) understanding 3-D effects on the mode of mantle convection on the basis of newly-developed scaling laws and published simulation results, (4) exploring the influence of the thermal evolution of the core on surface tectonics by a systematic investigation of coupled core-mantle evolution models, and (5) connecting internal mantle dynamics with surface observables, such as global sea level, plate velocity, and geomagnetic field strength, so that we can build falsifiable hypotheses for the evolution of mantle convection in the Precambrian.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.

板块构造是一类特殊的地幔对流类别，仅在太阳系中的地球行星中观察到地球。从产生大陆地壳到大气组成的调节，它负责大量地质过程。然而，关于其历史的一些基本问题尚未解决：当地球上构造构造以及它如何随着时间的流逝而发展时。该项目旨在通过前寒武纪（即，在5.4亿年前在5.4亿年前将推定的岩浆海洋凝固到phanerozoic的开始之后），通过建立强大的理论框架并探索其对地质和地球化学观察的含义，从而解决了可能的地幔对流模式。重建地球上板块构造的进化路径是最根本的地球物理问题之一，它为地质，地球物理和地球化学过程提供了全球环境，这项研究的潜在影响的半径几乎涵盖了固体地球科学的所有分支。预期的研究结果还应在整个地球行星的物理和化学中找到它们的应用，并有望成为可居住行星理论的一部分。该项目将为博士后同学和研究生提供支持和培训，以及本科生的暑期实习生或论文项目。 The planned research has the following five major objectives: (1) Establishing a regime diagram of mantle convection as a function of internal Rayleigh number, the temperature dependency of viscosity, yielding criteria, and the internal heating ratio, so that we can estimate how the mode of convection has evolved in the past, (2) quantifying the relation between quasi-steady-state solutions and transient situations, in terms of the mode of convection and heat-flow scaling, so that we can analyze collectively different numerical approaches to the evolving mantle dynamics in a unifying fashion, (3) understanding 3-D effects on the mode of mantle convection on the basis of newly-developed scaling laws and published simulation results, (4) exploring the influence of the thermal evolution of the core on surface tectonics by a systematic investigation of coupled core-mantle evolution models, and （5）将内部地幔动态与表面可观察物联系起来，例如全球海平面，板速度和地磁野外强度，以便我们可以在前寒武纪中建立可伪造的假设，以使地幔对流的演变发展。该奖项反映了NSF的法定任务，并通过评估范围的范围来反映出对基础的支持，并已被评估范围。