Project

Back to overview

Mantle Convection: Heat flux scaling and plume dynamics and heat transport in a plate tectonics-like regime

English title Mantle Convection: Heat flux scaling and plume dynamics and heat transport in a plate tectonics-like regime
Applicant Tackley Paul
Number 126773
Funding scheme Project funding
Research institution Institut für Geophysik ETH Zürich
Institution of higher education ETH Zurich - ETHZ
Main discipline Geophysics
Start/End 01.01.2010 - 31.12.2010
Approved amount 60'528.00
Show all

Keywords (8)

Mantle convection; heat tranport; heat flux; plate tectonics; slabs; hotspots; heat transport; geodynamics

Lay Summary (English)

Lead
Lay summary
The coupled system of mantle convection and plate tectonics is the engine that drives continental drift, mountain building, volcanoes, earthquakes, and indeed, all geological change on our planet. A central question is how has this system evolved over time: what was Earth like in the past? How did it evolve to the present state? How is heat extracted from the core to drive the geodynamo that generates the magnetic field?Understanding how the surface and core-mantle-boundary (CMB) heat fluxes in Earth's mantle convection-plate tectonics system scale with the relevant parameters is essential to understanding the thermal evolution of the mantle and core, a central problem in Earth science. While scalings for simple convective systems are well known, the presence of strongly temperature-dependent viscosity, plate tectonics, continents, a mixture of heating modes (basal, internal and secular cooling), and spherical geometry complicates the situation on Earth, making the top and bottom boundary layers asymmetric in both physical properties and heat flux. I this project we are conducting focused studies of CMB and surface heat flux in a plate tectonic regime using the tool of large-scale numerical modeling in 3D spherical geometry. Particular attention is being paid to the heat transport and dynamics of upwelling plumes and how this is affected by the details of plate tectonic environment (e.g., plate length). The research is being performed by a student at ETHZ and will form the basis of their Ph.D. dissertation.
Direct link to Lay Summary Last update: 21.02.2013

Responsible applicant and co-applicants

Employees

Name Institute

Associated projects

Number Title Start Funding scheme
112137 Mantle Convection: Heat flux scaling and plume dynamics and heat transport in a plate tectonics-like regime 01.01.2007 Project funding

Abstract

This proposal requests a fourth year of funding for an already funded PhD project. We request the additional year because the first phase of the project, i.e., studying basic questions of the generation of plate tectonics and convective planforms in 3D spherical geometry, has proven more interesting than originally envisioned and will result in two papers / thesis chapters befo-re the main goal of the project is reached (i.e., heat transport by plumes and slabs). Therefore this initial phase has taken longer then first imagined, but has been productive. Additionally these results facilitated performing two small, opportunistic subprojects, which were not part of the original plan, but have added significant value to the project without taking much additional time. These are discussed in the latest progress report, in summary: (i) using tracers in some of the calculations to study geochemical mixing, and (ii) scaling the results to large Earth-like planets ("super-Earths"), which are of increasing interest in the astronomical community. Both of these have been presented at international conferences. The next paragraph contains an updated version of the original summary.Understanding how the surface and core-mantle-boundary (CMB) heat fluxes in Earth’s mantle convection-plate tectonics system scale with the relevant parameters is essential to under-standing the thermal evolution of the mantle and core, a central problem in Earth science. While scalings for simple convective systems are well known, the presence of strongly temperature-dependent viscosity, plate tectonics, continents, a mixture of heating modes (basal, inter-nal and secular cooling), and spherical geometry complicates the situation on Earth, making the top and bottom boundary layers asymmetric in both physical properties and heat flux. Here we propose to conduct focused studies of CMB and surface heat flux in a plate tectonic regime using the tool of large-scale numerical modeling in 3D spherical geometry. Particular attention will be paid to the heat transport and dynamics of upwelling plumes and how this is affected by the details of plate tectonic environment (e.g., plate length). Additionally, these re-sults will be scaled to giant Earth-like planets ("super-Earths"), to make predictions for planets that are expected to be discovered soon, and to quantify the effect of plate tectonics and heating mode on the mixing of chemically-distinct species. The research will be the be performed over a 4 year period by a student at ETHZ and will form the basis of their Ph.D. dissertation.
-