A Cr isotopic study of the Bon Accord NiO body in the Barberton greenstone belt, South Africa

TitleA Cr isotopic study of the Bon Accord NiO body in the Barberton greenstone belt, South Africa
Publication TypeJournal Article
Year of Publication2014
AuthorsTredoux M., Roelofse F., Shukolyukov A.
JournalChemical Geology
Volume390
Pagination182-190
Date Published2014/12
Type of ArticleArticle
ISBN Number0009-2541
Accession NumberWOS:000345442400016
KeywordsArchaean; Barberton greenstone belt; chromium; core; Cr isotopes; Deep mantle; formation; geochemistry; mantle; mn-53-cr-53 systematics; Ni-rich rock; nickel-iron; origin; osmium; platinum-group minerals; solar-system; trace-elements
Abstract

An unusual oxide body, enriched in Ni and the platinum-group elements, was found in the north-western part of the Barberton greenstone belt, South Africa, in the 1920s. With mineralogy and geochemistry which are extremely anomalous, and do not conform to that of any other Ni-rich crustal rocks, it has been interpreted as either an Archaean paleo-meteorite or of terrestrial deep-mantle origin. Cr isotopic ratios were used to evaluate the merits of these two possibilities. Isotopic analyses returned values for epsilon(53) of 0.00 epsilon units, within a 2 s error, relative to a terrestrial standard. We interpret this information, together with trace element data from the surrounding peridotites, as pointing to a terrestrial origin for the body, and conclude that the current dataset is not inconsistent with a deep-mantle origin, as a remnant of core formation, with subsequent transport to and emplacement in the lithosphere by a mantle plume. (C) 2014 Elsevier B.V. All rights reserved.

DOI10.1016/j.chemgeo.2014.10.017
Short TitleChem. Geol.
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Student Publication: 
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