The HO and CO adsorption properties of phyllosilicate-poor palagonitic dust and smectites under martian environmental conditions

Jochen Jänchen , Richard V. Morris , David L. Bish , Mareike Janssen , Udo Hellwig

The recent detection of up to ∼10 wt.% water-equivalent H heterogeneously distributed in the upper meter of the equatorial regions of the martian surface and the presence of the 3-μm hydrations feature across the entire planet raises the question whether martian surficial dust can account for this water-equivalent H. We have investigated the HO and CO adsorption properties of palagonitic dust (<5 μm size fraction of phyllosilicate-poor palagonitic tephra HWMK919) as a martian dust analog and two smectites under simulated martian equatorial surface conditions. Our results show that the palagonitic dust, which contains hydrated and hydroxylated volcanic glass of basaltic composition, accommodates significantly more HO under comparable humidity and temperature conditions than do the smectites nontronite and montmorillonite.

Mots clés: Mars; Mineralogy; Geochemistry; Palagonite; Smectite; Water

Jochen Jänchen, Richard V. Morris, David L. Bish, Mareike Janssen, Udo Hellwig. The HO and CO adsorption properties of phyllosilicate-poor palagonitic dust and smectites under martian environmental conditions. Icarus, 2009, 200 (2), pp.463. ⟨10.1016/j.icarus.2008.12.006⟩. ⟨hal-00517245⟩