Role of anisotropic viscosity for computational modelling of convection in the Earth’s mantle

Convection within Earth’s mantle interior depends on rock deformation at depth. Recently this deformation has been shown to be anisotropic. This project will develop methods to incorporate this anisotropy into computer models of mantle convection.

Illustration

Estimates of the effective viscosity of sheared olivine, expressed relative to the viscosity for isotropic (untextured) mantle, for different geodynamic processes that deform textured olivine in different directions.

Our understanding of mantle convection depends critically on computer models that simulate the rock deformation occurring within the mantle interior. Recently, this rock deformation has been shown to be anisotropic, meaning that deformation happens more easily in some directions compared to others, depending on textures that form within the rock.

Simple models have shown that this “anisotropic viscosity” should exert a first-order influence on a wide range of deformations occurring within the solid earth. Despite its importance, anisotropic viscosity has not yet been incorporated into numerical models of geodynamic processes.

This project seeks to address this deficiency in two ways:

  1. Incorporate 3D anisotropy into geodynamic models to understand how rock texture and viscosity anisotropy affect mantle deformation processes.
  2. Train machine-learning algorithms (using the modeling results) to predict anisotropic viscosity from seismic observations of anisotropy (e.g. for mid-ocean ridge regions).

Both steps represent important computational advances, which we will use to constrain the influence of anisotropic viscosity for geodynamic problems such as seafloor spreading and time-dependent plate motions.

Requirements

  • MSc in physics, geology, or a related field.
  • Candidates should have experience in programming and a good understanding of plate tectonics and mantle dynamics.

Supervisors

Professor Clinton Phillips Conrad

Researcher Agnes Kiraly

Call 1: Project start autumn 2021

This project is in call 1, starting autumn 2021. Read about how to apply

Published Aug. 17, 2020 1:01 PM - Last modified Nov. 17, 2020 3:09 PM