“…Nevertheless, some influence cannot be ruled out. For example, non-altered impact melt fragments may mask the weak metal-OH feature near 2.2 μm observed in many spectra of bright areas (e.g., Murchie et al, 1993, Beinroth andArnold, 1996) and may contribute to the decrease in depth of the bound water band at 3 μm, which also shows significant spatial variations (Bibring et al, 1989Murchie et al, 1993;Calvin, 1997;Jouglet et al, 2007;Milliken et al, 2007). Recent analysis showed that a broad weak absorption band centered near 1.8 μm is present in most OMEGA spectra of bright regions (Le Mouélic et al, 2006;Combe et al 2008).…”