The origin of alteration “orangettes” in Dhofar 019: Implications for the age and aqueous history of the shergottites

Hallis, L.J. , Kemppinen, L., Lee, M.R. and Taylor, L.A. (2017) The origin of alteration “orangettes” in Dhofar 019: Implications for the age and aqueous history of the shergottites. Meteoritics and Planetary Science, 52(12), pp. 2695-2706. (doi: 10.1111/maps.12987)

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The shergottites are the largest group of Martian meteorites, and the only group that has not been found to contain definitive evidence of Martian aqueous alteration. Given recent reports of current liquid water at the surface of Mars, this study aimed to investigate in detail the possibility of Martian phyllosilicate within shergottite Dhofar 019. Optical and scanning electron microscopy, followed by transmission electron microscopy, confirmed the presence of alteration orangettes, with a layered structure consisting of poorly ordered Mg-phyllosilicate and calcite. These investigations identified maskelynite dissolution, followed by Mg-phyllosilicate and calcite deposition within the dissolution pits, as the method of orangette production. The presence of celestine within the orangette layers, the absence of shock dislocation features within calcite, and the Mg-rich nature of the phyllosilicate, all indicate a terrestrial origin for these features on Dhofar 019.

Item Type:Articles
Glasgow Author(s) Enlighten ID:Lee, Professor Martin and Hallis, Dr Lydia
Authors: Hallis, L.J., Kemppinen, L., Lee, M.R., and Taylor, L.A.
College/School:College of Science and Engineering > School of Geographical and Earth Sciences
Journal Name:Meteoritics and Planetary Science
ISSN (Online):1945-5100
Published Online:03 November 2017
Copyright Holders:Copyright © 2017 The Authors
First Published:First published in Meteoritics and Planetary Science 52(12): 2695-2706
Publisher Policy:Reproduced under a Creative Commons License

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Project CodeAward NoProject NamePrincipal InvestigatorFunder's NameFunder RefLead Dept
697411A journey from the solar nebula to planetary bodies: cycling of heat, water and organicsMartin LeeScience & Technology Facilities Council (STFC)ST/N000846/1SCHOOL OF GEOGRAPHICAL & EARTH SCIENCES