Question about Phoenix/Mars
On earth, process that tend to redistribute softer materials tend to generally increase the amount of materials in a spot (perpetually increasing sediment, for example) or scour them away (leaving the area cleared - rocky face). If opposing processes compete, then some sort of equilibrium is reached with a generally constant amount of the soft materials.
What's going on at Phoenix' site that there seems to be exactly a few centimeters of soil? Why doesn't it blow away or pile up?