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2008 Annual Science Report

Indiana University, Bloomington Reporting  |  JUL 2007 – JUN 2008

Stability of Methane Hydrates in the Presence of High Salinity Brines on Mars

Project Summary

Laboratory experiments were used to monitor the influence of increasing salinity on the stability of ices composed of water, methane, and carbon dioxide. New data show that these types of hydrates decease in stability as salinity increases, suggesting that lateral or vertical migration of brines in the subsurface of Mars could cause release of methane and carbon dioxide to surface sediments and the atmosphere. These experimental results are important for interpreting reports of methane in the Martian atmosphere.

4 Institutions
3 Teams
0 Publications
0 Field Sites
Field Sites

Project Progress

Stability of methane hydrates in the presence of high salinity brines on Mars

Progress report

Recent observations of methane in the highly oxidizing atmosphere of Mars suggest that methane has been added relatively recently. Several mechanisms for recent methane release have been proposed in the scientific literature including subsurface biological methanogenesis, abiogenic hydrothermal and/or volcanic activity, weathering of ultramafic deposits to serpentenites, dissociation of methane hydrates, atmospheric photolysis, or addition of organics via bolide impact. This laboratory study examines the effects of increasing salinity on gas hydrate stability and compares estimates of the Martian geothermal gradient to methane and carbon dioxide hydrate stability fields in the presence of high salinity brines. The results demonstrate that salinity increases alone result in a significant decrease in the predicted hydrate stability zone under conditions inferred to exit in the Martian subsurface. Thus, lateral or vertical movement of brines in the Martian subsurface may be a driving force in methane hydrate destabilization. Active thermal and/or pressure fluctuations are not required in order for methane hydrates to be the source of atmospheric methane.

    Tommy Phelps Tommy Phelps
    Project Investigator
    Susan Pfiffner

    Megan Elwood Madden

    Objective 2.1
    Mars exploration

    Objective 2.2
    Outer Solar System exploration

    Objective 3.1
    Sources of prebiotic materials and catalysts

    Objective 7.1
    Biosignatures to be sought in Solar System materials

    Objective 7.2
    Biosignatures to be sought in nearby planetary systems