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In Situ Measurement of Atmospheric Krypton and Xenon on Mars with Mars Science LaboratoryMars Science Laboratorys Sample Analysis at Mars (SAM) investigation has measured all of the stable isotopes of the heavy noble gases krypton and xenon in the martian atmosphere, in situ, from the Curiosity Rover at Gale Crater, Mars. Previous knowledge of martian atmospheric krypton and xenon isotope ratios has been based upon a combination of the Viking missions krypton and xenon detections and measurements of noble gas isotope ratios in martian meteorites. However, the meteorite measurements reveal an impure mixture of atmospheric, mantle, and spallation contributions. The xenon and krypton isotopic measurements reported here include the complete set of stable isotopes, unmeasured by Viking. The new results generally agree with Mars meteorite measurements but also provide a unique opportunity to identify various non-atmospheric heavy noble gas components in the meteorites. Kr isotopic measurements define a solar-like atmospheric composition, but deviating from the solar wind pattern at 80Kr and 82Kr in a manner consistent with contributions originating from neutron capture in Br. The Xe measurements suggest an intriguing possibility that isotopes lighter than 132Xe have been enriched to varying degrees by spallation and neutron capture products degassed to the atmosphere from the regolith, and a model is constructed to explore this possibility. Such a spallation component, however, is not apparent in atmospheric Xe trapped in the glassy phases of martian meteorites.
Document ID
20180001919
Document Type
Reprint (Version printed in journal)
Authors
Conrad, P. G. (NASA Goddard Space Flight Center Greenbelt, MD, United States)
Malespin, C. A. (NASA Goddard Space Flight Center Greenbelt, MD, United States)
Franz, H. B. (NASA Goddard Space Flight Center Greenbelt, MD, United States)
Pepin, R. O. (Minnesota Univ. Minneapolis, MN, United States)
Trainer, M. G. (NASA Goddard Space Flight Center Greenbelt, MD, United States)
Schwenzer, S. P. (Open Univ. Milton Keynes, United Kingdom)
Atreya, S. K. (Michigan Univ. Ann Arbor, MI, United States)
Freissinet, C. (Ecole Normale Superieure Paris, France)
Jones, J. H. (SGT, Inc. Houston, TX, United States)
Manning, H. (Concordia Coll. Moorhead, MN, United States)
Owen, T. (Hawaii Univ. Honolulu, HI, United States)
Pavlov, A. A. (NASA Goddard Space Flight Center Greenbelt, MD, United States)
Wiens, R. C. (Los Alamos National Lab. NM, United States)
Wong, M. H. (Michigan Univ. Ann Arbor, MI, United States)
Mahaffy, P. R. (NASA Goddard Space Flight Center Greenbelt, MD, United States)
Date Acquired
March 15, 2018
Publication Date
September 2, 2016
Publication Information
Publication: Earth and Planetary Science Letters
Volume: 454
ISSN: 0012-821X
Subject Category
Solar Physics
Statistics and Probability
Inorganic, Organic and Physical Chemistry
Lunar and Planetary Science and Exploration
Report/Patent Number
GSFC-E-DAA-TN40582
Distribution Limits
Public
Copyright
Other