Colloquium
Stability and dynamics of convection in dry salt lakes
Speaker: Lucas Goehring (Nottingham Trent University, England)
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.