  The gullies on Mars were discovered in the year 1999.Since then several
hypotheses have appeared trying to explain the presence of these gullies. The
main hypotheses are the ones which suggest that some liquid, water or CO2, was
responsible for modeling the gullies and ones that propose dry flows as the
modeling agents. The aim of this work is to develop an alternative hypotetical
mechanism of formation of Martian gullies.Our model proposes that the Martian
gullies were formed as a result of a fluidization process of the material
deposited on the slopes of the impact craters, plateaux and other
geomorphologic structures. This fluidization is caused by the sublimation of
carbon dioxide ice deposited in the form of snow, due to the daily and seasonal
temperature changes. We also present the results of an experimental
simulation.Structures similar to the Martian gullies were reproduced using the
air injection mechanism, as a substitute to gaseous CO2, on a sandy slope. The
Reynolds number for our experimental flow and for the flow in the Martian
gullies was calculated and we found that they are of the same order, whilst the
water flows have much higher Reynolds numbers.Taking into account the current
environmental conditions for Mars, from our results it may be suggested that
this mechanism is the possible modeling agent for the Martian gullies. Two of
the most important characteristics of the proposed model are: a) It offers a
simple explanation of how recurrent fluidization events occur in the same
place, a necessary recurrence of the formation of a gully, offering a
recharging mechanism for the system after every fluidization event, and b) It
considers the formation of gullies possible even in angles smaller than the
angle of repose. These characteristics of the model solve these two problems
present in current theories.
