Convection in a textured planet: morphology and dynamics of mid-ocean ridges on Earth and on Venus
From Laboratoire FAST, Univsersity of Paris Sud, France
Hosted by Clint Conrad & Björn H. Heyn
Understanding the details of plate accretion, failure and subduction remains a challenge due to the complex rheology of mantle rocks and of mantle lithosphere. However, soft matter such as silica colloids presents analogous rheological properties (from ductile to brittle, depending on temperature, composition, stress, texture, history,…) and therefore allows us to study the characteristics of convection and lithosphere dynamics in the laboratory. After a short summary of the different regimes of convection and types of subduction initiation observed in these fluids, I shall zoom on accretion processes. The experimental observations recover all the mechanical instabilities (transform faults, overlappers, microplates, …) of the mid-ocean ridges (MOR) observed on Earth. Scaling laws derived from the experiments not only give us insights into the dynamics of present-day Earth’s MORs, but also on the presence and dynamics of MOR on Venus, and on the Archean Earth.