View Full Version : Signs of water at Gusev

2004-Apr-29, 05:16 PM
Martian Water Science Early 2004 (http://www.spacedaily.com/news/mars-water-science-04d-printready.html)

The Gusev landing site of the first MER rover, "Spirit" -- which had seemed to be a relatively dull area of volcanic basalt rocks unaltered by water -- was finally starting to show some clear evidence of aqueous alteration after all.

2004-Apr-29, 10:00 PM
A very nice and informative piece, thanks. One problem with the idea of extremely acid waters on Mars is that these are likely to be highly ephemeral and local in nature. Acids are, by their nature, highly corrosive and react with rocks, at low temperatures forming silica and clays, at higher temperatures forming micas. Thus long lived water bodies tend to be self buffering. This is why the ocean as a pH of about 8. Significantly higher or lower pH's (such as >9 and <5) require special circumstances.

In terrestrial waters pH's below 5 are are unusual, and are typically associated with high levels of organic activity, either producing organic acids, as in peat bogs and forest waters (pH as low as 4), or sulphide oxidation (locally as low as -2 in mine waste). Ferrolysis by ferrous iron by stagnant saline groundwater may led to pH as low as 2.5, but this is debated (at least by me and a colleague).


2004-Apr-29, 11:36 PM
Thanks ToSeek. This would be analysis of the rock that some people on this very board (heh) were thinking might be a chunk of ice.