Using MGS and Odyssey data, combined with developments in the study of glaciers, scientists suggest that glaciers once existed on Pavonis Mons and probably still do to some extent. Evidence for this includes concentric ridges (moraines dropped by glaciers), a knobby area (caused by ice sublimating), and a smooth section that flows over other deposits (debris-covered glacial ice). The ice could have been deposited when the tilt of Mars changed the climate, thereby causing more moisture to be present in the atmosphere. Studies suggest the glaciation happened in the Late Amazonian period, the most recent period in Mars chronology. Multiple stages of glaciation probably occurred. The ice present today represents one more resource for possible future colonization of the planet.