Interesting THEMIS images of Mars of late.
Also, the report that olivine [apparently a common mineral in rocky celestial bodies] easily breaks down in the presence of H2O is rather intriquing.
This is where you come in Nick [or Dr. Blackwell]...

If the bottom of those martian canyons and valleys show a lack of olivine mineral, in those THEMIS images, wouldn't that be considered compellingly strong evidence [or even proof] that H20 [not CO2] was responsible for carving those same Areographic features?
I'm curious what you think.

Someone else will have to provide
the URLs for the THEMIS images by the way.

cheers.

Jacob