Introduction: Martian ejecta blankets exhibits single layers and double layer ejecta that are likely the result of emplacement by fluidized processes, either from impact into and vaporization of subsurface volatiles (Barlow et al., 2000) or by ejecta entrainment by the thin Martian atmosphere (Barnouin-Jha and Schultz, 1998). One of the main goals of the MarsExpress mission is the detection of volatile materials by means of OMEGA imaging spectroscopy, of radar sounding (MARSIS) and high resolution images of the surface (HRSC camera). It has been proposed that fluidized ejecta lobes would originate from the melting of ice rich permafrost or from the vaporization of water or volatiles (Carr et al., 1977, Gault and Greeley, 1978, Schults, 1994). The detection of potential hydrated minerals would comfort such hypotheses. In that context, we have used the OMEGA data to analyze the surface composition of fluidized ejecta lobes. The data acquired during the first two years of the mission already reveal only a few examples of lobate ejecta with hydrated minerals. Here we discuss their geological context and their implications for Martian climate and subsurface volatiles. Background: The OMEGA investigation on board MarsExpress is currently mapping the surface composition of Mars at a 0.3 to 5 kilometer resolution by means of visible-near-infrared hyperspectral imagery (Bibring et al, 2005). The data already acquired reveal a diverse surface mineralogy with the identification of large deposits of phyllosilicates mainly associated with Noachian outcrops consistent with an early active hydrological system (Poulet et al., 2005). The presence of sulfates results from a more acidic environment.