Posted by Mike Kremer on Mar 18, 2002 at 11:09
(62.188.151.218)
Re: Not Dry Ice, but Real Ice on Mars Today (Dale)
Expanding upon your answer, and to my own question.
Obviously you are right when you say "The conditions on Mars lead to a large concentration of CO2 on the surface"
Right, the reason being that all the lighter gases would have long left Mars for outer space.
Its gravitation would only be able to hold down
the heavy gases such as CO2 and Nitrogen. The other reason for CO2 (at least here on Earth) is
due to subduction of the continental shelve, heating and melting the Calcium Carbonate in the rocks, which is released as CO2 via vents and volcanic action.
With regard water or CO2 made gullies. My speculation is that water must have etched out the gullies eons ago. Since they are too wide deep and extensive for it to have been anything other than water? Then again one could assume that Mars a smaller and internally cooler planet than Earth, was not able to cover its surface in Lava or Granite (molten rock) in the same way as Earth. Therefore water might have easily worn away its friable surface far faster than here on Earth? Before it escaped into space. i.e Mars could have produced its gullies using far less water than we realise.
Prehaps the 'explosive slurry of CO2 and Ice is only able to produce the far finer filigree type of channels out of the sides of the main gullies which we are seeing (active?) today.
Liquid CO(2) is not going to just materialize Amaranth Rose 20/3 19:35
(3)