Martian xenon components in Shergotty mineral separates: Locations, sources, and trapping mechanisms
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CitationOcker, K. D., & Gilmour, J. D. (2004). Martian xenon components in Shergotty mineral separates: Locations, sources, and trapping mechanisms. Meteoritics & Planetary Science, 39(12), 1967-1981.
PublisherThe Meteoritical Society
JournalMeteoritics & Planetary Science
AbstractIsotopic signatures and concentrations of xenon have been measured in Shergotty mineral separates by laser step heating. Martian atmosphere and martian interior xenon are present, as is a spallation component. Martian atmospheric xenon is 5-10 times more concentrated in opaque minerals (magnetite, ilmenite, and pyrrhotite) and maskelynite than in pyroxenes, perhaps reflecting grain size variation. This is shown to be consistent with shock incorporation. A component consisting of solar xenon with a fission contribution, similar to components previously identified in martian meteorites and associated with the martian interior, is best defined in the pyroxene-dominated separates. This component exhibits a consistent 129Xe (129Xe/132Xe ~1.2) excess over solar/planetary (129Xe/132Xe ~1.04). We suggest that gas present in the melt, perhaps a mixture of interior xenon and martian atmosphere, was incorporated into the pyroxenes in Shergotty as the minerals crystallized.