RobVG wrote:
If the assumption is correct then shouldn't there be higher concentrations of salt (chlorine) in the basins on mars?

Alex writes:
Yes, though I agree (to first order) that the chlorine signal is suggestive of halides, or even evaporite deposits. Mind you, the resolution of the instrument is such that correlating Cl signals to specific geologic units may be difficult at best. At any rate, one might also note that Odyssey's GRS suite (primarily the Neutron Spectrometer) requires relatively low integration times (~15 hours for 10% relative uncertainty in concentrations) to detect Cl. I'll be interested in the "details" (i.e., error bars, signal strength, etc.) before I really get excited.

Alex R. Blackwell
University of Hawaii