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Methane bursts as a trigger for intermittent lake-forming climates on post-Noachian Mars

Kite, Edwin S. and Gao, Peter and Goldblatt, Colin and Mischna, Michael A. and Mayer, David P. and Yung, Yuk L. (2017) Methane bursts as a trigger for intermittent lake-forming climates on post-Noachian Mars. Nature Geoscience, 10 (10). pp. 737-740. ISSN 1752-0894. https://resolver.caltech.edu/CaltechAUTHORS:20170821-105332756

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Abstract

Lakes existed on Mars later than 3.6 billion years ago, according to sedimentary evidence for deltaic deposition. The observed fluviolacustrine deposits suggest that individual lake-forming climates persisted for at least several thousand years (assuming dilute flow). But the lake watersheds’ little-weathered soils indicate a largely dry climate history, with intermittent runoff events. Here we show that these observational constraints, although inconsistent with many previously proposed triggers for lake-forming climates, are consistent with a methane burst scenario. In this scenario, chaotic transitions in mean obliquity drive latitudinal shifts in temperature and ice loading that destabilize methane clathrate. Using numerical simulations, we find that outgassed methane can build up to atmospheric levels sufficient for lake-forming climates, if methane clathrate initially occupies more than 4% of the total volume in which it is thermodynamically stable. Such occupancy fractions are consistent with methane production by water–rock reactions due to hydrothermal circulation on early Mars. We further estimate that photochemical destruction of atmospheric methane curtails the duration of individual lake-forming climates to less than a million years, consistent with observations. We conclude that methane bursts represent a potential pathway for intermittent excursions to a warm, wet climate state on early Mars.


Item Type:Article
Related URLs:
URLURL TypeDescription
https://doi.org/10.1038/ngeo3033DOIArticle
https://www.nature.com/articles/ngeo3033PublisherArticle
http://rdcu.be/wotXPublisherFree ReadCube access
https://arxiv.org/abs/1611.01717arXivDiscussion Paper
ORCID:
AuthorORCID
Kite, Edwin S.0000-0002-1426-1186
Gao, Peter0000-0002-8518-9601
Mischna, Michael A.0000-0002-8022-5319
Yung, Yuk L.0000-0002-4263-2562
Alternate Title:Duration and rapid shutdown of post-Naochian lake-forming climates on Mars explained by methane bursts
Additional Information:© 2017 Macmillan Publishers Limited, part of Springer Nature. Received 25 May 2017; Accepted 23 August 2017; Published online 02 October 2017. We are grateful for input from D. E. Archer, J. C. Armstrong, B. L. Ehlmann, V. E. Hamilton, A. D. Howard, R. P. III Irwin, M. C. Palucis, D. Stolper, R. M. E. Williams and R. Wordsworth. We thank J. F. Kasting and A. G. Fairén for useful reviews. Part of the research was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration. We acknowledge the University of Chicago’s Research Computing Center and financial support from NASA (NNX16AG55G, NNX15AM49G). Author Contributions: E.S.K. designed research; M.A.M., Y.L.Y. and D.P.M. contributed new models, model output, and analyses; E.S.K., C.G. and P.G. carried out research; and E.S.K. wrote the paper. The authors declare no competing financial interests. Code availability: The methane burst code is available from the corresponding author upon request. The GCM and photochemical codes are not available. Data availability: The materials that support the findings of this study and the figures in this paper, including computer code, are available from the corresponding author upon request.
Group:Astronomy Department
Funders:
Funding AgencyGrant Number
NASA/JPL/CaltechUNSPECIFIED
NASANNX16AG55G
NASANNX15AM49G
Issue or Number:10
Record Number:CaltechAUTHORS:20170821-105332756
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20170821-105332756
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:80639
Collection:CaltechAUTHORS
Deposited By: George Porter
Deposited On:02 Oct 2017 20:18
Last Modified:20 Apr 2020 08:47

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