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Petrology of igneous clasts in Northwest Africa 7034: Implications for the petrologic diversity of the martian crust

Santos, Alison R.; Agee, Carl B.; McCubbin, Francis M.; Shearer, Charles K.; Burger, Paul V.; Tartèse, Romain and Anand, Mahesh (2015). Petrology of igneous clasts in Northwest Africa 7034: Implications for the petrologic diversity of the martian crust. Geochimica et Cosmochimica Acta, 157 pp. 56–85.

DOI (Digital Object Identifier) Link: https://doi.org/10.1016/j.gca.2015.02.023
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Abstract

The martian meteorite Northwest Africa (NWA) 7034 was examined both petrographically and geochemically using several micro-beam techniques including electron probe microanalysis and secondary ion mass spectrometry. We have identified various clast types of igneous, sedimentary, and impact origin that occur within the breccia, and we define a classification scheme for these materials based on our observations, although our primary focus here is on the petrology of the igneous clasts. A number of different igneous clasts are present in this meteorite, and our study revealed the presence of at least four different igneous lithologies (basalt, basaltic andesite, trachyandesite, and an Fe, Ti, and P (FTP) rich lithology). These lithologies do not appear to be related by simple igneous processes such as fractional crystallization, indicating NWA 7034 is a polymict breccia that contains samples from several different igneous sources. The basalt lithologies are a good match for measured rock compositions from the martian surface, however more exotic lithologies (e.g., trachyandesite and FTP lithologies) show this meteorite contains previously unsampled rock types from Mars. These new rock types provide evidence for a much greater variety of igneous rocks within the martian crust than previously revealed by martian meteorites, and supports recent rover observations of lithologic diversity across the martian surface. Furthermore, the ancient ages for the lithologic components in NWA 7034 indicate Mars developed this lithologic diversity in the early stages of crust formation.

Item Type: Journal Item
Copyright Holders: 2015 Elsevier Ltd
ISSN: 0016-7037
Project Funding Details:
Funded Project NameProject IDFunding Body
Research grantST/I001298/1Science and Technology Facilities Council (STFC)
Keywords: NWA 7034; martian meteorite
Academic Unit/School: Faculty of Science, Technology, Engineering and Mathematics (STEM) > Physical Sciences
Faculty of Science, Technology, Engineering and Mathematics (STEM)
Research Group: Space
Item ID: 44308
Depositing User: Mahesh Anand
Date Deposited: 24 Sep 2015 14:28
Last Modified: 08 May 2019 13:39
URI: http://oro.open.ac.uk/id/eprint/44308
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