Salinity‐induced hydrate dissociation: A mechanism for recent CH<sub>4</sub> release on Mars

Madden, M. E. Elwood; Ulrich, Shannon; Onstott, Tullis C.; Phelps, Tommy J.

doi:10.1029/2006gl029156

Cited by 22 publications

(7 citation statements)

References 47 publications

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“…This is potentially important to subpermafrost geochemistry, as CH 4 hydrate formation and dissipation can affect gas chemical composition and fluid chemical and isotopic composition (Trofimuk et al 1974; Hesse and Harrison 1981; Milkov et al 2004). The subsurface temperature and pressure conditions at the U‐tube sample depth were within the CH 4 hydrate stability field, given the salinity of the matrix fluid (Elwood Madden et al 2007). Owing to the lack of gas quantity data, it was not possible to confirm the presence of CH 4 hydrates.…”

Section: Discussionmentioning

confidence: 99%

Hydrogeology, Chemical and Microbial Activity Measurement Through Deep Permafrost

et al. 2011

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Little is known about hydrogeochemical conditions beneath thick permafrost, particularly in fractured crystalline rock, due to difficulty in accessing this environment. The purpose of this investigation was to develop methods to obtain physical, chemical, and microbial information about the subpermafrost environment from a surface-drilled borehole. Using a U-tube, gas and water samples were collected, along with temperature, pressure, and hydraulic conductivity measurements, 420 m below ground surface, within a 535 m long, angled borehole at High Lake, Nunavut, Canada, in an area with 460 m thick permafrost. Piezometric head was well above the base of the permafrost, near land surface. Initial water samples were contaminated with drill fluid, with later samples <40% drill fluid. The salinity of the non-drill fluid component was <20,000 mg/L, had a Ca/Na ratio above 1, with δ 18O values ~5‰ lower than the local surface water. The fluid isotopic composition was affected by the permafrost-formation process. Nonbacteriogenic CH 4 was present and the sample location was within methane hydrate stability field. Sampling lines froze before uncontaminated samples from the subpermafrost environment could be obtained, yet the available time to obtain water samples was extended compared to previous studies. Temperature measurements collected from a distributed temperature sensor indicated that this issue can be overcome easily in the future. The lack of methanogenic CH 4 is consistent with the high sulfate concentrations observed in cores. The combined surface-drilled borehole/U-tube approach can provide a large amount of physical, chemical, and microbial data from the subpermafrost environment with few, controllable, sources of contamination.

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Section: Discussionmentioning

confidence: 99%

Hydrogeology, Chemical and Microbial Activity Measurement Through Deep Permafrost

et al. 2011

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“…However, clathrates are also known to be unstable in the presence of salts since both species compete for water (e.g., Elwood Madden et al. ; Safi et al. ).…”

Section: Freezing Of the Oceanmentioning

confidence: 99%

Insights into Ceres's evolution from surface composition

Castillo‐Rogez

Neveu

McSween

et al. 2018

Meteorit & Planetary Scien

101

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Inspired by the recent results of the Dawn mission, thermodynamic models of rock alteration and brine evaporation have been used to help understand the conditions under which water-rock interaction took place within the dwarf planet Ceres. This analysis constrains Ceres's early history and offers a framework within which future observations may be interpreted. A broad range of alteration conditions have been simulated using the Geochemist's Workbench and PHREEQC software, associated with the FREZCHEM model that constrains the consequences of freezing the liquid phase in equilibrium with the observed mineralogical assemblage. Comparison of the modeling results with observed surface mineralogy at Ceres indicates advanced alteration under a relatively high fugacity of hydrogen, a conclusion that is consistent with predictions for, and observations of, large icerich bodies. The simulations suggest production of methane that could help regulate the redox environment and possibly form clathrate hydrates upon freezing of the early ocean. The detection of localized occurrences of natrite (sodium carbonate) at the surface of Ceres provides key constraints on the composition of fluids that are necessarily alkaline. In addition, the combined hydrothermal and freezing simulations suggest that hydrohalite may be abundant in Ceres's subsurface, similar to Earth's polar regions. The global homogeneity of Ceres's surface, made of material formed at depth, suggests a large-scale formation mechanism, while local heterogeneities associated with impact craters and landslides suggest that some form of sodium carbonate and other salts are accessible in the shallow subsurface.

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“…In fact, in some of the areas from where methane emissions appear to have originated, retreating glaciers have been detected (Head et al 2005). A related version of this idea is that the hydrate dissociation and CH 4 release is triggered by small changes in salinity (Elwood Madden et al 2007). The Planetary Fourier Spectrometer experiment on board Mars Express has shown that methane correlates well with the water vapour in the atmosphere and with the near-surface ice-enriched areas at middle and low latitudes identified by Mars Odyssey (Formisano 2005).…”

Section: Methane In the Martian Atmospherementioning

confidence: 99%

The case for life on Mars

Schulze‐Makuch¹,

Fairén

Dávila

2008

International Journal of Astrobiology

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There have been several attempts to answer the question of whether there is, or has ever been, life on Mars. The boldest attempt was the only ever life detection experiment conducted on another planet: the Viking mission. The mission was a great success, but it failed to provide a clear answer to the question of life on Mars. More than 30 years after the Viking mission our understanding of the history and evolution of Mars has increased vastly to reveal a wetter Martian past and the occurrence of diverse environments that could have supported microbial life similar to that on Earth for extended periods of time. The discovery of Terran extremophilic microorganisms, adapted to environments previously though to be prohibitive for life, has greatly expanded the limits of habitability in our Solar System, and has opened new avenues for the search of life on Mars. Remnants of a possible early biosphere may be found in the Martian meteorite ALH84001. This claim is based on a collection of facts and observations consistent with biogenic origins, but individual links in the collective chain of evidence remain controversial. Recent evidence for contemporary liquid water on Mars and the detection of methane in the Martian atmosphere further enhance the case for life on Mars. We argue that, given the cumulative evidence provided, life has and is likely to exist on Mars, and we have already found evidence of it. However, to obtain a compelling certainty a new mission is needed, one which is devoted to the detection of life on Mars.

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Salinity‐induced hydrate dissociation: A mechanism for recent CH₄ release on Mars

Cited by 22 publications

References 47 publications

Hydrogeology, Chemical and Microbial Activity Measurement Through Deep Permafrost

Hydrogeology, Chemical and Microbial Activity Measurement Through Deep Permafrost

Insights into Ceres's evolution from surface composition

The case for life on Mars

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Salinity‐induced hydrate dissociation: A mechanism for recent CH4 release on Mars

Cited by 22 publications

References 47 publications

Hydrogeology, Chemical and Microbial Activity Measurement Through Deep Permafrost

Hydrogeology, Chemical and Microbial Activity Measurement Through Deep Permafrost

Insights into Ceres's evolution from surface composition

The case for life on Mars

Contact Info

Product

Resources

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Salinity‐induced hydrate dissociation: A mechanism for recent CH₄ release on Mars