You might want to check out this one:

NEW PERSPECTIVES ON MARS SURFACE MINERALOGY FROM THE INFRARED IMAGING.
http://gsa.confex.com/gsa/2004AM/finalprogram/abstract_81352.htm

It discusses the infrared spectrometer observations from Mars Express. It mentions the observation of nontronite, which is a type of clay. This is interesting because it had been previously argued that the lack of detection of clays on Mars is an indication of the lack of extensive water on the planet.
Also notable is the discussion of extensive sulfate deposits in Aram Chaos, Arabia, and Meridiani Terra. Interesting since Arabia also shows high hydrogen content from Mars Odyssey.