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Low temperature production and exhalation of methane from serpentinized rocks on Earth: A potential analog for methane production on Mars

Etiope, Giuseppe and Ehlmann, Bethany L. and Schoell, Martin (2013) Low temperature production and exhalation of methane from serpentinized rocks on Earth: A potential analog for methane production on Mars. Icarus, 224 (2). pp. 276-285. ISSN 0019-1035. https://resolver.caltech.edu/CaltechAUTHORS:20130723-114829501

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Abstract

We evaluate, based on terrestrial analogs, the potential flux, origin and isotopic signature of methane (CH_4) from serpentinized or serpentinizing rocks on Mars. The Tekirova ophiolites, in Turkey, have been shown to release, either via focused vents or through diffuse microseepage, substantial amounts of CH_4 which could be produced via catalyzed abiotic methanation (Sabatier reaction) at low temperatures (<50 °C). Serpentinized ultramafic rocks on Mars are likely to have necessary chemical constituents for methane production and fractures for release of gas to the atmosphere, similar to those on Earth. A simple, first-order estimation gas-advection model suggests that methane fluxes on the order of several mg m^(−2) d^(−1), similar to microseepage observed in terrestrial ophiolites, could occur in martian rocks. High temperature, hydrothermal conditions may not be necessary for abiotic CH_4 synthesis on Mars: low temperature (<50 °C) methanation is possible in the presence of catalysts like ruthenium, rhodium or, more commonly, chromium minerals, which occur in terrestrial ophiolites as in martian mantle meteorites. The terrestrial analog environment of abiotic microseepage may thus explain production of methane on Mars in the ancient past or at present. The wide range of martian ^(12)C/^(13)C and D/H ratios and the potential secondary alteration of CH_4 by abiotic oxidation, as observed on Earth, could result in large isotope variations of methane on Mars. CH_4 isotopic composition alone may not allow definitive determination of biotic vs. abiotic gas origin. Using our terrestrial vs. martian analysis as guide to future Mars exploration we propose that direct methane and ethane gas detection and isotopic measurements on the ground over serpentinized/serpentinizing rocks should be considered in developing future strategies for unraveling the source and origin of methane on Mars.


Item Type:Article
Related URLs:
URLURL TypeDescription
http://dx.doi.org/10.1016/j.icarus.2012.05.009DOIArticle
http://www.sciencedirect.com/science/article/pii/S0019103512001832PublisherArticle
ORCID:
AuthorORCID
Ehlmann, Bethany L.0000-0002-2745-3240
Additional Information:© 2012 Elsevier Inc. Available online 14 May 2012. This work is part of the "Interdisciplinary Study of Methane on Mars" funded by the Research and Scientific Support Department of the European Space Agency (ESA-RSSD) and coordinated by Olivier Witasse. Ravindranathan Thampi provided useful inputs about catalyzed methanation. Thanks are due to three anonymous reviewers for their valuable comments and suggestions to improve the paper.
Funders:
Funding AgencyGrant Number
European Space Agency (ESA)UNSPECIFIED
Subject Keywords:Mars; Earth; Geological processes; Mineralogy
Issue or Number:2
Record Number:CaltechAUTHORS:20130723-114829501
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20130723-114829501
Official Citation:Giuseppe Etiope, Bethany L. Ehlmann, Martin Schoell, Low temperature production and exhalation of methane from serpentinized rocks on Earth: A potential analog for methane production on Mars, Icarus, Volume 224, Issue 2, June 2013, Pages 276-285, ISSN 0019-1035, http://dx.doi.org/10.1016/j.icarus.2012.05.009. (http://www.sciencedirect.com/science/article/pii/S0019103512001832)
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:39529
Collection:CaltechAUTHORS
Deposited By: Jason Perez
Deposited On:23 Jul 2013 20:43
Last Modified:09 Mar 2020 13:18

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