Early Mars: Reconciling Climate And Geochemistry
R. Wordsworth1,2,*, A. H. Knoll2, J. Hurowitz3, M. Baum2, B. Ehlmann4,5, J. Head6, K. Steakley7 And F. Ding1.
1
School Of Engineering And Applied Sciences, Harvard University. 2department Of Earth And Planetary Sciences,
Harvard University. 3department Of Geosciences, Stony Brook University. 4division Of Geological And Planetary
Sciences, California Institute Of Technology. 5jet Propulsion Laboratory, Nasa. 6department Of Geological Sciences, Brown University. 7space Science And Astrobiology Division, Nasa Ames Research Center / Bay Area Environmental Research Institute. *Rwordsworth@Seas.Harvard.Edu.
Introduction: The Last Few Years Has Seen Substantial
Progress On Our Understanding Of The Faint Young Sun
Problem And The Nature Of Mars’S Early Climate. Nonetheless, Significant Uncertainties Remain. Here, We Discuss Some Of Our Progress On The Early Mars Climate
Problem Since The Last Mars Atmosphere Workshop,
With A Focus On Two Issues: The Degree To Which The
Early Climate Was Permanently Vs. Episodically Warm,
And The Extent To Which Scenarios For Warming Can Be
Reconciled With The Rich Geochemical Record Observed
By Both Rovers And Orbiters.
Observational Evidence: Extensive Geologic Evidence Indicates That 3-4 Ga, Surface Conditions On
Mars Were Dramatically Different, With Multiple Episodes Of Fluvial Erosion, Aqueous Alteration And Sediment Deposition [1]. The Most Plausible Explanation
For This Is Greenhouse Warming From A Thicker Early
Atmosphere, Although The Details Continue To Be Debated [2,3]. Various Analyses Suggest That In Total, Between 104 And 107 Years Of Warm Conditions Were Required To Erode Observed Valley Networks, Deposit Sediment In Craters And Form Weathering Sequences [4-7].
In Addition, Abundant Ancient Exposures Of Unaltered