Salt Polygons and Porous Media Convection

Abstract

From fairy circles to patterned ground and columnar joints, natural patterns spontaneously appear in many complex geophysical settings. Here, we investigate the origins of polygonally patterned crusts of salt playa and salt pans. 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. We show that they 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, analog experiments, and numerical simulations, we further determine the conditions under which salt polygons should form, as well as how their characteristic size emerges.6 MoreReceived 1 June 2022Revised 5 December 2022Accepted 25 January 2023DOI:https://doi.org/10.1103/PhysRevX.13.011025Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI. Open access publication funded by the Max Planck Society.Published by the American Physical SocietyPhysics Subject Headings (PhySH)Research AreasGeophysical fluid dynamicsGeophysicsPattern formationTechniquesChaos & nonlinear dynamicsFluid DynamicsNonlinear DynamicsInterdisciplinary Physics