Relative abundances of argon, krypton, and xenon in the Martian atmosphere as measured in Martian meteorites

We determined the concentrations of trapped Ar, Kr, and Xe in impact-melt glasses from Shergotty, Y793605, and two inclusions of EET79001 not previously analyzed. When combined with literature noble gas data on a single glass inclusion in EET79001 and a glass vein in Zagami, these data give more accurate estimates of the composition of Martian atmospheric gases trapped in these glasses. For the geological recent composition of the Martian atmospheric we infer Xe-129/Xe-132 = 2.60 +/- 0.05, Ar-36/Xe-132 = 900 +/- 100, and Kr-84/Xe-132 = 20.5 +/- 2.5. These elemental ratios differ from those measured by Viking by factors of 2.5 and 1.8, respectively. The Ar-36/Xe-132 and Kr-84/Xe-132 ratios in ALH84001 are considerably less than those in impact glasses and suggest preferential adsorption tin carbonate?) of Xe over Ar and Xe over Kr by factors of similar to 11 and similar to 2.6, respectively. We suggest that noble gases dissolved in water may have largely determined the trapped noble gas abundance pattern in ALH84001. Copyright (C) 1998 Elsevier Science Ltd.