关于这张图
During periods in Mars' history when the planet had greater axial tilt, shifts in atmospheric circulation may have favored the extensive accumulation of snow in some locations. Protonilus Mensae is just such a site of extensive glaciation. We can see a flow of material through the valleys between a complex of small mesas. Streamlines and flow fronts appear as subtle ridges. Some ridges appear perpendicular to the mesas indicating flow direction. Others appear concentric to the mesas and parallel to the valleys, where debris and now-underlying ice bunched up and moved down valley. Deflation o…
