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runoff from frozen martian highlands CONCLUSIONS Barnhart, C.J., Howard, A.D., and Moore, J.M.,
(Wordsworth et al., 2017). 1. Total solar-energy production is increas- 2009, Long-term precipitation and late-
Multispectral imaging, lander observa- ing gradually due to well-understood stage valley network formation: Landform
simulations of Parana Basin, Mars: Journal of
tions, and the content of meteorites derived physics controlling rates of thermonu- Geophysical Research, v. 114, E01003, https://
from Mars indicate that olivine is common clear fusion in the solar core (Bahcall et doi.org/10.1029/2008JE003122.
on Mars (e.g., McSween et al., 2006; al., 2001). A more massive and luminous Bradley, A., and Summons, R.E., 2010, Multiple
Koeppen and Hamilton, 2008; Ody et al., young Sun is not supported by recent origins of methane at the Lost City Hydro-
thermal Field: Earth and Planetary Science
2013). Hydrous alteration (serpentiniza- astrophysical studies. Letters, v. 297, p. 34–41, https://doi.org/
tion) of olivine and pyroxene by ground- 2. Archean sedimentary rocks on Earth 10.1016/j.epsl.2010.05.034.
water should have been common if not include many indicators of liquid water Burbidge, E.M., Burbidge, G.R., Fowler, W.A.,
pervasive early in martian history (Oze at Earth’s surface, including sedimen- and Hoyle, F., 1957, Synthesis of the elements
in stars: Reviews of Modern Physics, v. 29,
and Sharma, 2005, 2007). Serpentinization tary rocks containing evidence of micro- no. 4, p. 547–650, https://doi.org/10.1103/
yields H , which in turn reacts with CO to bial life that in turn indicate open water RevModPhys.29.547.
2
2
produce CH , as is seen in hydrothermal with sunlight. The warm Archean Earth Burron, I., da Costa, G., Sharpe, R., Fayek, M.,
4
fluids associated with ultramafic rocks resulted from high atmospheric concen- Gauert, C., and Hofmann, A., 2018, 3.2 Ga
on Earth (Bradley and Summons, 2010). trations of CO , with possible additional detrital uraninite in the Witwatersrand Basin,
2
South Africa: Evidence of a reducing Archean
Cooling of the young martian crust in the warming from methane and hydrogen, atmosphere: Geology, v. 46, p. 295–298,
presence of groundwater would result in lower cloud albedo, a low ratio of land https://doi.org/10.1130/G39957.1.
formation of a near-surface cryosphere of to water at Earth’s surface, and other Catling, D.C., and Kasting, J.F., 2017, Atmospheric
frozen groundwater. Downward propaga- factors. It is not clear which additional Evolution on Inhabited and Lifeless Worlds:
New York, Cambridge University Press, 579 p.,
tion of the boundary between frozen factors were dominant or if we are https://doi.org/10.1017/9781139020558.
ground and deeper groundwater would missing something fundamental. Charnay, B., Forget, F., Wordsworth, R., Leconte,
trap dissolved methane in methane clath- 3. Abundant evidence of martian river J., Millour, E., Codron, F., and Spiga, A., 2013,
rate, which is water ice with ~6% methane channels and crater lakes at ca. 3.3–3.9 Exploring the faint young Sun problem and the
trapped within the cage-like molecular Ga indicates warm conditions in other- possible climates of the Archean Earth with a
3-D GCM: Journal of Geophysical Research,
structure of the clathrate ice (e.g., wise icy highlands of equatorial and v. 118, p. 10,414–10,431, doi:10.1002/jgrd.50808.
Kvenvolden, 1993; Prieto-Ballesteros et southern Mars. Although transient Charnay, B., Le Hir, G., Fluteau, F., Forget, F.,
al., 2006). As a result of clathrate genesis, melting might occur under favorable and Catling, D.C., 2017, A warm or a cold
the early martian cryosphere could have orbital parameters, augmentation of early Earth? New insights from a 3-D
climate-carbon model: Earth and Planetary
become a global methane reservoir (Lasue such warming by a few percent atmo- Science Letters, v. 474, p. 97–109, https://
et al., 2015). Furthermore, the cryosphere spheric H and CH released from doi.org/10.1016/j.epsl.2017.06.029.
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would become an impermeable cap for crustal or mantle reservoirs may be a Chassefière, E., Lasue, J., Langlais, B., and
trapped gaseous H and CH , as on Earth viable solution to the faint young Sun Quesnel, Y., 2016, Early Mars serpentinization-
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4
(Kvenvolden, 1993). problem for Mars. derived CH reservoirs, H -induced warming
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and paleopressure evolution: Meteoritics &
Methane and hydrogen liberated to the Planetary Science, v. 51, no. 11, p. 2234–2245,
atmosphere by cryosphere disruption and ACKNOWLEDGMENTS https://doi.org/10.1111/maps.12784.
I thank James Kasting and an anonymous
melting from magmatism, impacts, and reviewer for comments that improved clarity Claire, M.W., Kasting, J.F., Domagal-Goldman,
perhaps outburst floods, would result in and focus. S.D., Stüeken, E.E., Buick, R., and Meadows,
V.S., 2014, Modeling the signature of sulfur
minor to perhaps significant transient mass-independent fractionation produced in
planetary warming. Such warming might the Archean atmosphere: Geochimica et
have been sufficient to cause snow and REFERENCES CITED Cosmochimica Acta, v. 141, p. 365–380,
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(Wordsworth et al., 2017). Finally, the Sciences of the United States of America, crust in cold environments: Science Advances,
10 –10 years needed for river valley inci- v. 106, no. 24, p. 9548–9555, https://doi.org/ v. 2, no. 2, e1500368, https://doi.org/10.1126/
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