Liquid CO₂ breakout and the formation of recent small gullies on Mars

Abstract

We show that the action of a CO 2 suspended flow could have produced the recent small gullies on Mars, and, hence, that liquid water is not required. The model involves the build‐up of a liquid‐CO 2 aquifer behind and below a dry‐ice barrier (dam/cap rock) in the pore spaces a few meters into the rock from the cliff face and on order of a hundred meters below the top of the cliff brink surface. Seasonal (or obliquity‐cycle‐seasonal) heating causes pinching out of the dry‐ice barrier and rapid release of the liquid CO 2 . Erosion of the gullies occurs as the rapid vaporization of the liquid CO 2 with entrainment of rock and clathrate‐hydrate ice produces a density flow analogous to a terrestrial nue ardente.