Brain-terrain-like features in the Qaidam Basin: Implications for various morphological features on Mars

Abstract

“Brain terrain” is a type of patterned ground composed of sinuous ridges and troughs. It is widespread in mid-high latitude regions on Mars and has been interpreted to be formed by sublimation of ground ice. In the Qaidam Basin, a geomorphological analog for Mars, ridge-and-trough landforms similar to Martian brain terrain were discovered. In the eastern basin, brain-terrain-like features are distributed on soft and porous surfaces near a wet playa. As the ridges are primarily composed of detritus, brain-terrain-like features in the eastern Qaidam Basin might be formed by aeolian depositional processes with minor components of cementing salts. In the western basin, brain-terrain-like features are located on compact and hard surfaces of dry playas. The ridges are salt crusts that expanded and thrust at the margin of salt plates, while the troughs are the depressions that trapped aeolian sediments. Given the similarity between brain-terrain-like features in the eastern basin and brain terrain on Mars, aeolian processes might be involved in the formation of some Martian brain terrain. As brain-terrain-like features in the eastern basin are neither megaripples nor dunes, they might also represent a rare analog for transverse aeolian ridges on Mars. Brain-terrain-like features in the western basin are structures on salt crusts, which could be analogs at meter-scale complex textures of possible chloride-bearing units on Mars. The brain terrain type features found in the Qaidam Basin did not form through ice-related processes. Their similarities to features on Mars therefore suggest that some of the brain terrain type features on Mars could also form through aeolian and salt-related processes.