Description:

Why did life evolve on Earth but not on other known terrestrial planets? One of the necessary ingredients for planetary habitability is long-term climate stability, which on Earth is achieved through the interplay between oceans, atmosphere, and rocky layers. Rocks make up most of the Earth’s volume. Thus, rock deformation governs the formation of tectonic plates and all their attendant phenomena, such as mountain building, earthquake cycles, volcanism, and other geological processes, including the long-term carbon cycle and climate variation. Other terrestrial planets in our Solar System are mostly made up of rocks as well and are compositionally similar to Earth, and yet they do not have plate tectonics, liquid oceans or complex life. In my research, I develop new physical models of rock deformation to understand the evolution of terrestrial planets and explain their divergent paths, focusing on surface dynamics and tectonic regimes. In this talk, I will present a new microphysical model that captures co-evolution and interactions between different crystalline defects that accommodate strain at conditions characteristic of planetary mantles and lithospheres. The model yields a new deformation map that makes new predictions for mechanical properties of rocks, such as stiffening and weakening over stress-ranges that covers transition from diffusion to dislocation creep regimes. The new model is not restricted to steady state conditions, but readily captures transient microstructural changes and resultant changes in material strength.

Elvira Mulyukova, Assistant Professor, Department of Earth and Planetary Sciences, Northwestern University

Host: Istvan Kovacs