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Terrestrial and Martian weathering signatures of xenon components in shergottite mineral separates
Author(s) -
CARTWRIGHT J. A.,
OCKER K. D.,
CROWTHER S. A.,
BURGESS R.,
GILMOUR J. D.
Publication year - 2010
Publication title -
meteoritics and planetary science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.09
H-Index - 100
eISSN - 1945-5100
pISSN - 1086-9379
DOI - 10.1111/j.1945-5100.2010.01101.x
Subject(s) - martian , xenon , atmosphere of mars , meteorite , geology , martian surface , weathering , astrobiology , mineral , geochemistry , mars exploration program , mineralogy , chemistry , physics , organic chemistry
– Xenon‐isotopic ratios, step‐heating release patterns, and gas concentrations of mineral separates from Martian shergottites Roberts Massif (RBT) 04262, Dar al Gani (DaG) 489, Shergotty, and Elephant Moraine (EET) 79001 lithology B are reported. Concentrations of Martian atmospheric xenon are similar in mineral separates from all meteorites, but more weathered samples contain more terrestrial atmospheric xenon. The distributions of xenon from the Martian and terrestrial atmospheres among minerals in any one sample are similar, suggesting similarities in the processes by which they were acquired. However, in opaque and maskelynite fractions, Martian atmospheric xenon is released at higher temperatures than terrestrial atmospheric xenon. It is suggested that both Martian and terrestrial atmospheric xenon were initially introduced by weathering (low temperature alteration processes). However, the Martian component was redistributed by shock, accounting for its current residence in more retentive sites. The presence or absence of detectable 129 Xe from the Martian atmosphere in mafic minerals may correspond to the extent of crustal contamination of the rock’s parent melt. Variable contents of excess 129 Xe contrast with previously reported consistent concentrations of excess 40 Ar, suggesting distinct sources contributed these gases to the parent magma.