Nick,

I know this is probably old news for you but I was surfing around the web and noticed a map of Mars showing hematite concentrations on Mars based upon THEMIS data. Apparently there is an isolated (almost unique) area on Mars with very high concentrations of hematite. This area is Sinus Meridiani. I believe Sinus Meridiani is a prime landing site for Mars Exploration Rover. To me, this seems to be a very wise choice for a landing site. What in your opinion would be the mechanism for producing hematite on Mars? Is a non-aqueous process for hematite production possible? Can hematite percipitate out of liquid water if there is no free oxygen present?

I don't understand enough about the chemistry of haematite to really be definitive on this one, but based on my experience with many other minerals I'm fairly sure that there are other ways to form it.

However, this COULD be evidence of a deep hydrothermal system that has been eroded into.

I also noticed with some dismay that Gusev Crater is amongst the top 4 sites selected as possible MER landing sites. I thought Mars Global Surveyor produced pictures refuting the notion that Gusev Crater was an ancient lake (no observable shorelines). It seems(?) to me that Gusev is just another crater with a gully in it. Why is Gusev still being considered?

There are several factions within the MER assessment team. One is a strong Blue Mars faction - Nathalie Cabrol is an important member of that faction and as a result, one of that faction's favourites was voted in. Science is just a fancy form of politics with equations attached (as you must know from internal Ames politics!).

No surprise (for me) that Mars Odyssey is seeing initial indications of large deposits of hydrogen (ice). As an advocate for Mars colonization, I would find the discovery of near surface ice on Mars to be excellent news. I believe(?) it was your opinion that the Martian ice cryosphere was deep under the regolith. If this is true, then would it be possible for Mars Odyssey to detect it or is this indeed near surface ice?

The report relates exclusively to near-polar measurements where everyone (even me!) agrees that shallow/surface ice exists.

The instruments have a maximum penetration depth of ~ 1 metre so have no hope of finding buried H2O whether it be at depths of 1 km or 10 10 km.

OTOH, if it detected pulses of H signal over M&E gullies, that would be clear evidence for a water-related origin for them and I would have to fold my hand (in that game, at least).