Is Release of Martian Atmosphere from Polar Clathrate the Cause of the Nakhlite and ALH84001 Ar/Kr/Xe Ratios?

Variations in the Ar/Kr/Xe ratios of martian atmosphere trapped in martian meteorites correlate with the time of ejection of these meteorites from Mars. We suggest that these variations reflect actual differences in the Ar/Kr/Xe ratios of the martian atmosphere at the time of ejection of the meteorites. We propose that the variation of the Ar/Kr/Xe ratios of the martian atmosphere is caused by time varying uptake and release of these gases by CO 2-H 2O clathrate-hydrate in the polar caps. Nakhlites, martian meteorites representing cumulate magmatic rocks, contain evidence of atmosphere from the time of their ejection from Mars. We postulate that the martian atmosphere at that time had lower Ar/Xe and Kr/Xe ratios compared with the modern atmosphere because of the release of these and other gases from polar clathrate, possibly during a period of high (∼60°) obliquity.