Colloquium

Stability and dynamics of convection in dry salt lakes

Speaker: Lucas Goehring (Nottingham Trent University, England)

Date and time
Venue
Auditorium

Abstract

From fairy circles to patterned ground and columnar joints, natural patterns spontaneously appear in many complex geophysical settings. Here, I will discuss the origins of polygonally patterned crusts of salt playa and saltpans. These beautifully regular features, approximately a meter in diameter, are found worldwide and are fundamentally important to the transport of salt and dust in arid regions. I will show how these patterns are consistent with the surface expression of buoyancy-driven convection in the porous soil beneath a salt crust. By combining quantitative results from direct field observations, analogue experiments and numerical simulations, I will show how salt polygons can form from such a convective instability, as well as how their characteristic size emerges.

Lucas Goehring

Lucas Goehring is a Professor of Physics at the Nottingham Trent University, England. He obtained his PhD degree in 2008 from the University of Toronto. He is an expert in non-linear dynamics and pattern formation, and his research has focused on multi-phase flows and a variety of interdisciplinary topics. He has worked extensively at the interface between soft matter physics and other areas including biology, the earth sciences and heritage science. His work on geophysical patterns has helped explain the scaling of columnar joint such as the Giant’s Causeway, the dynamics of permafrost crack patterns on Earth and Mars, the formation of Precambrian fossils as hydrodynamic instabilities, the patterning of salt crusts in dry lakes, and the failure of materials from artificial sandstone to avalanches.