Mars Mission
01- Canals
02- Mariners
03- Riverbeds
04- Sub-surface Ice
05- Fleet
06- Martian Ice
07- Slope Streaks
08- Water Found
09- Phyllocian Era
10- Theikian Era
11- Siderikan Era
12- Martian Regions
13- Obliquity
14- Martian Tectonics
15- Topographic Morph
16- Crustal Magnetism
17- Original Impact
18- Polar Regions
19- Hydrated Minerals
20- Theikian Warming
21- New Phoenix Snow
22- Equatorial Glaciers
23- Ancient Ice
24- Continental Snow Drift

23 - Ancient Ice

A snowy Valles Marineris

 

One theory to account for how glaciers could form so far from the poles relates, again, to the idea that Mars' obliquity fluctuated extremely in the past.

"The glaciers were formed from snow brought from the polar regions," says Brown University planetary geologist James Head. "A few million years ago, Mars had a different tilt. The poles were pointing more closely toward the Sun, so the polar ice caps released massive amounts of water vapor into the atmosphere. Wind carried the vapor south, up and over the slopes of the Tharsis Montes volcanoes and Olympus Mons, the solar system's largest volcano. The vapor cooled, condensed and fell as snow. The snow turned to ice over time and formed glaciers.

   
  Alan Lambert 2009