Evidence Of Obliquity Drven Climate Fluctuations On
Mars From Small Crater Surveys
M. E. Hoffman, H. E. Newsom, University Of New Mexico, Albuquerque, Nm, Usa (Mehoffman13@Unm.Edu),
F. Calef, Jet Propulsion Laboratory, California Institute Of Technology, Pasadena, Ca, Usa. J. P. Williams,
University Of Los Angeles, Los Angeles, California, Usa

Introduction: The Obliquity, Or Axial Tilt Of
Mars Has Been Theorized To Fluctuate Quasichaotically Over Semi-Periodic Timescales [1]. Modeling The Obliquity History Of Mars For The Most Recent 20 Ma Is Supported By Measurements Of The
Layered Deposits At The Martian Poles [2]. For Timescales Beyond 20 Ma, The Obliquity Fluctuations Become Increasingly Chaotic And Impossible To Predict
Without Additional Constraints.
Fluctuations In The Martian Obliquity Result In
Changes In The Atmosphere As The Co2 Ice Reservoir At
The Poles (Largely Concentrated At The South Pole) Is
Coupled With The Predominantly Co2 Martian Atmosphere [2] (Figure 1). At Higher Angles Of Obliquity,
>40 Degrees, The Martian Poles Experience Higher
Amounts Of Solar Insolation. This Results In Greater
Sublimation Of The Co2 Ice At The Poles, Which Increases The Amount Of Atmospheric Co2 And Causes
An Increase In The Atmospheric Pressure And Density.
At Lower Obliquities, <40 Degrees, The Poles Experience Less Solar Insolation And Are Able To Accumulate
Co2 Ice At The Poles. This Scenario Results In More