TY - JOUR
T1 - Seasonal melting and the formation of sedimentary rocks on Mars, with predictions for the Gale Crater mound
AU - Kite, Edwin S.
AU - Halevy, Itay
AU - Kahre, Melinda A.
AU - Wolff, Michael J.
AU - Manga, Michael
N1 - U.S. taxpayer through NASA [NNX08AN13G, NNX09AN18G, NNX09AL20G, NNX11AF51G]; NSF [TG-EAR100023]; Weizmann Institute of Science; Israeli Committee for Higher Education; Caltech; O.K. Earl FellowshipIt is a pleasure to thank the following people for their generosity with time, ideas and data. We are grateful to Richard Brandt and Steve Warren for sharing the radiation code underlying (Brandt and Warren, 1993). Paul Niles and anonymous reviewers wrote stimulating, thorough, and fair reviews. This work was triggered by discussions with Oded Aharonson, Jeff Andrews-Hanna, and Devon Burr. Discussions with Mark Allen, Konstantin Batygin, Bill Cassata, Bill Dietrich, Bethany Ehlmann, John Eiler, Woody Fischer, John Grotzinger, Alex Hayes, Jim Head, Joel Hurowitz, Ross Irwin, Gary Kocurek, Misha Kreslavsky, Mike Lamb, Vedran Lekic, Alejandro Soto, Ken Tanaka, Aaron Wolf and Robin Wordsworth supplied us with new ideas and refined our existing ones. E.S.K. is grateful to Oded Aharonson, Woody Fischer, Francois Forget, John Grotzinger, Kevin Lewis, Joannah Metz, Mikki Osterloo, Robin Wordsworth, and James Wray for sharing their preprints and datasets. This research was supported by the U.S. taxpayer through NASA Grants NNX08AN13G, NNX09AN18G, and NNX09AL20G (to M.M.), NNX11AF51G (to Oded Aharonson), and NSF Teragrid allocation TG-EAR100023. I.H. acknowledges support from a Sir Charles Clore Prize for Outstanding Appointment in the Experimental Sciences at the Weizmann Institute of Science, and an Alon Fellowship for Young P.I.s from the Israeli Committee for Higher Education. E.S.K. is supported at Caltech by an O.K. Earl Fellowship.
PY - 2013/3
Y1 - 2013/3
N2 - A model for the formation and distribution of sedimentary rocks on Mars is proposed. In this model (ISEE-Mars), the rate-limiting step is supply of liquid water from seasonal melting of snow or ice. The model is run for a O(102) mbar pure CO2 atmosphere, dusty snow, and solar luminosity reduced by 23%. For these conditions snow melts only near the equator, when obliquity and eccentricity are high, and when perihelion occurs near equinox. These requirements for melting are satisfied by 0.01-20% of the probability distribution of Mars' past spin-orbit parameters. This fraction is small, consistent with the geologic record of metastable surface liquid water acting as a "wet-pass filter" of Mars climate history, only recording orbital conditions that permitted surface liquid water. Total melt production is sufficient to account for observed aqueous alteration. The pattern of seasonal snowmelt is integrated over all spin-orbit parameters and compared to the observed distribution of sedimentary rocks. The global distribution of snowmelt has maxima in Valles Marineris, Meridiani Planum and Gale Crater. These correspond to maxima in the sedimentary-rock distribution. Higher pressures and especially higher temperatures lead to melting over a broader range of spin-orbit parameters. The pattern of sedimentary rocks on Mars is most consistent with a model Mars paleoclimate that only rarely produced enough meltwater to precipitate aqueous cements (sulfates, carbonates, phyllosilicates and silica) and indurate sediment. This is consistent with observations suggesting that surface aqueous alteration on Mars was brief and at low water/rock ratio. The results suggest intermittency of snowmelt and long globally-dry intervals, unfavorable for past life on Mars. This model makes testable predictions for the Mars Science Laboratory Curiosity rover at Gale Crater's mound (Mount Sharp, Aeolis Mons). Gale Crater's mound is predicted to be a hemispheric maximum for snowmelt on Mars.
AB - A model for the formation and distribution of sedimentary rocks on Mars is proposed. In this model (ISEE-Mars), the rate-limiting step is supply of liquid water from seasonal melting of snow or ice. The model is run for a O(102) mbar pure CO2 atmosphere, dusty snow, and solar luminosity reduced by 23%. For these conditions snow melts only near the equator, when obliquity and eccentricity are high, and when perihelion occurs near equinox. These requirements for melting are satisfied by 0.01-20% of the probability distribution of Mars' past spin-orbit parameters. This fraction is small, consistent with the geologic record of metastable surface liquid water acting as a "wet-pass filter" of Mars climate history, only recording orbital conditions that permitted surface liquid water. Total melt production is sufficient to account for observed aqueous alteration. The pattern of seasonal snowmelt is integrated over all spin-orbit parameters and compared to the observed distribution of sedimentary rocks. The global distribution of snowmelt has maxima in Valles Marineris, Meridiani Planum and Gale Crater. These correspond to maxima in the sedimentary-rock distribution. Higher pressures and especially higher temperatures lead to melting over a broader range of spin-orbit parameters. The pattern of sedimentary rocks on Mars is most consistent with a model Mars paleoclimate that only rarely produced enough meltwater to precipitate aqueous cements (sulfates, carbonates, phyllosilicates and silica) and indurate sediment. This is consistent with observations suggesting that surface aqueous alteration on Mars was brief and at low water/rock ratio. The results suggest intermittency of snowmelt and long globally-dry intervals, unfavorable for past life on Mars. This model makes testable predictions for the Mars Science Laboratory Curiosity rover at Gale Crater's mound (Mount Sharp, Aeolis Mons). Gale Crater's mound is predicted to be a hemispheric maximum for snowmelt on Mars.
UR - http://www.scopus.com/inward/record.url?scp=84872259039&partnerID=8YFLogxK
U2 - 10.1016/j.icarus.2012.11.034
DO - 10.1016/j.icarus.2012.11.034
M3 - مقالة
SN - 0019-1035
VL - 223
SP - 181
EP - 210
JO - Icarus
JF - Icarus
IS - 1
ER -