Sub-surface deposits of hydrous silicates or hydrated magnesium sulfates as hydrogen reservoirs near the Martian equator : plausible or not?
- Clair I.
- James W.
- David T.
- William C.
- David L.
Neutron maps obtained using the neutron spectrometer (NS) and the high-energy neutron detector aboard the Mars Odyssey spacecraft reveal variations in the concentration of hydrogen over the martian low to middle latitudes, with up to {approx}10 wt% water-equivalent hydrogen in some equatorial regions. Infrared spectroscopic data provide evidence of chemically and/or physically bound H{sub 2}O and/or OH. Likewise, the decrease in flux of epithermal neutrons in Arabia Terra and southwest of Olympus Mons has been attributed to enhanced concentration of water-bearing minerals in the subsurface. The near-surface martian regolith is expected to contain both unweathered and weathered materials. It may contain significant and heterogeneously distributed amounts of hydrous minerals, such as clays, zeolites, and/or salt hydrates, such as MgSO{sub 4} {center_dot} nH{sub 2}O. Experimental studies suggest that if such water-bearing minerals formed in the past on the martian surface, they may retain significant amounts of water under present martian surface conditions. Hydrous minerals could thus account for some or all of the water observed in the martian regolith by Odyssey. Our study uses surface P-T data to predict regions of stability and the hydration state of selected water-bearing minerals from low to middle latitudes and to identify the nature and amount of hydrous minerals that could possibly account for the water observed by NS.
- Research Organization:
- Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)
- Sponsoring Organization:
- USDOE
- OSTI ID:
- 977407
- Report Number(s):
- LA-UR-04-0288; LA-UR-04-288; TRN: US201009%%742
- Resource Relation:
- Conference: Submitted to: Proceedings, Lunar and Planetary Science Conference, League City, TX, March 15-19, 2004
- Country of Publication:
- United States
- Language:
- English
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