Geomorphological features in the Gavkhoni playa lake, Se Esfahan, Iran

Abstract

Common features on the sand flat are gypsiferous marl mounds, gypsum interlayers, thin efflorescent salt crust, puffy surface and tufa. The first four features suggest periodic flooding and desiccation. Bi-carbonate-rich springs probably built small tufa mounds. Hard porous surface pitted by small holes with a few centimeters wide and deep is remarkable morphology on the mud flat/saline mud flat. This results from flooding, desiccation and evaporation of capillary brines and rapid and differential rising of the sedimentary surface. Polygonal halite crusts, halite pressure ridges and efflorescent cauliflowers (popcorn) are common features on the salt pan. They suggest volume reduction caused by either thermal contraction or desiccation and pumping of subsurface brine and subsequent evaporation along the cracks between the polygons.