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Magnesian ilmenite in picritic basalts from the Karoo Province, South Africa

Published online by Cambridge University Press:  05 July 2018

R. Grant Cawthorn ,
John W. Bristow  and
David I. Groves
R. Grant Cawthorn
Affiliation:
Geology Department, University of the Witwatersrand, Wits, 2050, South Africa
John W. Bristow
Affiliation:
Geology Department, De Beers Consolidated Mines, Box 47, Kimberley, 8300, South Africa
David I. Groves
Affiliation:
Geology Department, University of Western Australia, Nedlands, 6009, Australia
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Abstract

Some picritic lavas from near the base of the volcanic succession in the Lebombo region of the Karoo Province contain phenocrysts of olivine and skeletal microphenocrysts of ilmenite, the latter indicating rapid crystallization from the magma. These ilmenite grains contain up to 6% MgO. The near-liquidus crystallization and the high MgO content of the ilmenite are highly anomalous for ilmenite in tholeiitic rocks. These features reflect the atypical nature (high MgO and TiO2) of the parental magma and/or highly reduced conditions of crystallization.

Keywords

magnesian ilmeniteilmenitebasaltsKaroo ProvinceSouth Africa
Type
Research Article
Information
Mineralogical Magazine , Volume 53 , Issue 370 , April 1989 , pp. 245 - 252
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 1989

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