The analysis of water in the Martian regolith

Anderson, Duwayne M.; Tice, Allen R.

doi:10.1007/bf01732365

Cited by 37 publications

(21 citation statements)

References 9 publications

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“…The neighborhood of the Viking 1 landing site was chosen for this purpose. Although previous determinations of the water content of surface soils are very uncertain, the best guess at the time was 1% within a factor of three based on the work of Houck et al [1973], Biemann et al [1977], and Anderson and Tice [1979]. A discussion of the measurements from which the water content of surface soils was determined and their uncertainties is presented elsewhere [ Feldman et al , 2004].…”

Section: Previous Analysis Of Water Near the South Pole Using Mars Odmentioning

confidence: 99%

Composition and structure of the Martian surface at high southern latitudes from neutron spectroscopy

et al. 2004

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[1] Neutron spectroscopy data acquired by Mars Odyssey are analyzed to determine the abundance and depth of near-surface water ice as a function of latitude in the southern hemisphere as well as the inventory of CO 2 in the south polar residual cap. The surface is modeled as a semi-infinite, water-rich permafrost layer covered by desiccated material, which is consistent with theoretical models of ground ice stability. Latitude-dependent parameters, water abundance and depth, are determined from zonally averaged neutron counting data. Spatial mixing of the output of neutrons from regions within the footprint of the spectrometer is modeled, and asymmetrical features such as the residual cap are included in the analysis. Absorption of thermal neutrons by major elements other than hydrogen is found to have a significant influence on the determination of water abundance. Poleward of À60°, the water-rich layer contains 60% ± 10% water by weight (70% to 85% by volume) and is covered by less than 15 g/cm 2 ± 5 g/cm 2 of dry material. The volume fraction of water is generally higher than can be accommodated in the pore space of surface soils, which implies that water vapor diffusion processes alone cannot explain the observations. Alternatives for the formation of the water-rich layer are discussed. Results of our analysis of the residual-cap CO 2 inventory support conclusions that the atmosphere is not buffered by a larger reservoir of surface CO 2 at the poles and that Mars' total CO 2 inventory is well represented by the present atmospheric mass.

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Section: Previous Analysis Of Water Near the South Pole Using Mars Odmentioning

confidence: 99%

Composition and structure of the Martian surface at high southern latitudes from neutron spectroscopy

et al. 2004

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“…The adsorption of water by Martian soil has been suggested to be an important part of the water-cycle on Mars (Anderson and Tice, 1979). Hence, the study of adsorption of water by smectites, proposed to be major components of the Martian soils, is important in that a significant portion of the water present on Mars may be contained in such clays (as well as in other forms, such as permafrost).…”

Section: W a T E R Adsorption Isothermsmentioning

confidence: 99%

Laboratory investigations of mars: Chemical and spectroscopic characteristics of a suite of clays as Mars Soil Analogs

Banin

Carle

Chang

et al. 1988

Origins Life Evol Biosphere

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Two major questions have been raised by prior explorations of Mars. Has there ever been abundant water on Mars? Why is the iron found in the Martian soil not readily seen in the reflectance spectra of the surface? The work reported here describes a model soil system of Mars Soil Analog Materials, MarSAM, with attributes which could help resolve both of these dilemmas. The first set of MarSAM consisted of a suite of variably iron/calcium-exchanged montmorillonite clays. Several properties, including chemical composition, surface-ion composition, water adsorption isotherms, and reflectance spectra, of these clays have been examined. Also, simulations of the Viking Labeled Release Experiment using the MarSAM were performed. The results of these studies show that surface iron and adsorbed water are important determinants of clay behavior as evidenced by changes in reflectance, water absorption, and clay surface reactions. Thus, these materials provide a model soil system which reasonably satisfies the constraints imposed by the Viking analyses and remote spectral observations of the Martian surface, and which offers a sink for significant amounts of water. Finally, our initial results may provide insights into the mechanisms of reactions that occur on clay surfaces as well as a more specific approach to determining the mineralogy of Martian soils.

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“…In Earth's extreme environments, micro-organisms arc known to metabolize in thin liquid water veins or films with thicknesses as small as a few monolayers (e.g. in desert environments) to as much as a few microns contained on and within soil and ice matrices (Nersesova 1950;Anderson 1968: Anderson & Tice 1979Thiel & Madey 1987;Williams & Smith 1989: Chuvilian e t a/. 1998Henderson 2002;Price 2007).…”

Section: Introductionmentioning

confidence: 99%

Adsorbed water and thin liquid films on Mars

Boxe

Hand

Nealson

et al. 2012

International Journal of Astrobiology

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At present, bulk liquid water on the surface and near-subsurface of Mars does not exist due to the scarcity of condensed-and gas-phase water, pressure and temperature constraints. Given that the nuclei of soil and ice, that is, the soil solid and ice lattice. respectively, are coated with adsorbed and/or thin liquid films of water well below 273 K and the avai lability of water limits biological activity. we quantify lower a nd upper limits for the thickness of such adsorbed/water films on the surface of the Martian regolith and for subsurface ice. These limits were calculated based on experimental and theoretical data for pure water ice and water ice containing impurities, where water ice containing impurities exhibit thin liquid film enhancements, ranging from 3 to 90. Close to the cold limit ofwat~.::r stabil ity (i.e. 273 K), thin liquid film thicknesses at the surface of the Martian regolith is 0.06 nm (pure water icc) and ranges from 0.2 to 5 nm (water icc with impurities). An adsorbed water layer of 0.06 nm implies a dessicated surface as the thickness of one monolayer of water is 0.3 nm but represents 0.001-0.02% of the Martian atmospheric water vapour inventory. Taking into account the specific surface a rea (SSA) of surface-soil (i.e. top I mm of regolith and 0.06 nm adsorbed water layer), shows Martian surface-soil may contain interfac ial water that represents 6 66% of the upper-and lower-limit atmospheric water vapour inventory and almost four times and . 13°/.,, the lower-and upper-limit Martian atmospheric water vapour inventory. Similarly, taking the SSA of Martian soil, the top I mm or regolith at 5 nm thin liquid water thickness, yields 1.10 x I OIJ and 6.50 x I OIJ lit res of waters, respectively, 55-325 times larger than Mars' atmospheric water vapour inventory. %, respectively, of the Martian atmospheric water vapour inventory. Thin liquid film thicknesses on/in subsurface ice were investigated via two scenarios: (i) under the idealistic case where it is asswncd that the diurnal thermal wave is equal to the temperature of icc tens of centimetres below the surface, allowing for such icc to experience temperatures close to 273 K and (ii) under the, likely, realistic scenario where the diurnal thermal wave allows for the maximum subsurface ice temperature of 235 Kat I m depth between 30°N and 30°S. Scenario I yields thin liquid film thicknesses ranging from II to 90 nm: these amounts represent 4 x I 0 6 3.0 x I 0 7 litres of water. For pure water ice, Sce nario 2 reveals that the thickness of thin liquid films contained on/within Martian subsurface is less than 1.2 nm , several molecular layers thick. Conversely, via Lhc cfTect of impurities a t 235 K a llows for a thin liquid film thickness on/within subsurface icc of 0.5 nm , corresponding to 6.0 x I 0 4 litrcs of water. The existence of thin films on Mars is supported by data from the Mars Exploration Rovers (MERs) Spirit and Opportunity's Alpha Proton X-ray Spectrometer instrumentation. which have detected increased levels of brom...

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The analysis of water in the Martian regolith

Cited by 37 publications

References 9 publications

Composition and structure of the Martian surface at high southern latitudes from neutron spectroscopy

Composition and structure of the Martian surface at high southern latitudes from neutron spectroscopy

Laboratory investigations of mars: Chemical and spectroscopic characteristics of a suite of clays as Mars Soil Analogs

Adsorbed water and thin liquid films on Mars

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