Volumetric Changes of Mud on Mars: Evidence from Laboratory Simulations

Abstract

We present results of experiments performed inside a low-pressure chamber designed to investigate whether the volume of mud changes when exposed to a Martian atmospheric pressure. Depending on the mud viscosity, we observe a volumetric increase of up to 30% at the pressure of ∼6 mbar. The reason is that the low pressure causes instability of the water within the mud, leading to profuse bubble formation that increases the volume of the mixture. This mechanism bears resemblance to the volumetric changes associated with the degassing of terrestrial lava or mud volcano eruptions caused by a rapid ascend along the conduit and associated pressure drop.