Effect of bridgmanite-ferropericlase grain size evolution on Earth's average mantle viscosity: implications for mantle convection in early and present-day Earth.

ABSTRACT: Recent experimental investigations of grain size evolution in bridgmanite-ferropericlase assemblages have suggested very slow growth for these bimodal phases. Despite numerous speculations on grain size-dependent viscosity, a comprehensive test with realistic grain size evolution parameters compatible with the lower mantle has been lacking. In this study, we develop self-consistent 2-D spherical half-annulus geodynamic models of Earth's evolution using the finite volume code StagYY to assess the role of grain size on lower mantle viscosity. We explore several models with and without grain size evolution to compare their effects on mantle viscosity. In models with grain size evolution, we consider three scenarios: (1) uniform grain growth throughout the entire mantle with a composite rheolo

SUBMITTER: Paul J 

PROVIDER: S-EPMC11615032 | biostudies-literature | 2024

REPOSITORIES: biostudies-literature