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Noble gas adsorption with and without mechanical stress: not Martian signatures but fractionated air

Schwenzer, Susanne P.; Herrmann, Siegfried and Ott, Ulrich (2012). Noble gas adsorption with and without mechanical stress: not Martian signatures but fractionated air. Meteoritics & Planetary Science, 47(6) pp. 1049–1061.

DOI (Digital Object Identifier) Link: http://dx.doi.org/10.1111/j.1945-5100.2012.01373.x
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Abstract

Sample preparation, involving physical and chemical methods, is an unavoidable step in geochemical analysis. From a noble gas perspective, the two important effects are loss of sample gas and/or incorporation of air, which are significant sources of analytical artifacts. This article reports on the effects of sample exposure to laboratory air without mechanical influence and during sample grinding. The experiments include pure adsorption on terrestrial analog materials (gibbsite and olivine) and grinding of Martian meteorites. A consistent observation is the presence of an elementally fractionated air component in the samples studied. This is a critical form of terrestrial contamination in meteorites as it often mimics the heavy noble gas signatures of known extra-terrestrial end-members that are the basis of important conclusions about the origin and evolution of a meteorite. Although the effects of such contamination can be minimized by avoiding elaborate sample preparation protocols, caution should be exercised in interpreting the elemental ratios (Ar/Xe, Kr/Xe), especially in the low-temperature step extractions. The experiments can also be transferred to the investigation of Martian meteorites with long terrestrial residence times, and to Mars, where the Mars Science Laboratory mission will be able to measure noble gas signatures in the current atmosphere and in rocks and soils collected on the surface in Gale crater.

Item Type: Journal Article
Copyright Holders: 2012 The Meteoritical Society
ISSN: 1945-5100
Project Funding Details:
Funded Project NameProject IDFunding Body
Not SetNot SetGerman Science Foundation (Grants Jo305-1 ⁄ 1, Ot171 ⁄ 3-4, and Schw1232 ⁄ 1-1
Keywords: noble gases, fractionated air, contamination, laboratory, xenon, Martian meteorites, Martian atmosphere
Academic Unit/Department: Science > Physical Sciences
Interdisciplinary Research Centre: Centre for Earth, Planetary, Space and Astronomical Research (CEPSAR)
Item ID: 33980
Depositing User: Susanne Schwenzer
Date Deposited: 11 Jul 2012 11:37
Last Modified: 16 Nov 2012 12:27
URI: http://oro.open.ac.uk/id/eprint/33980
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