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Minor and trace element chemistry of carbonates, apatites and magnetites in some African carbonatites

Published online by Cambridge University Press:  05 July 2018

J. B. Dawson ,
I. M. Steele ,
J. V. Smith  and
M. L. Rivers
J. B. Dawson
Affiliation:
Department of Geology and Geophysics, University of Edinburgh, West Mains Road, Edinburgh EH9 3JW, UK
I. M. Steele
Affiliation:
Department of Geophysical Sciences, University of Chicago, 5734 S. Ellis Ave, IL 60637, USA
J. V. Smith
Affiliation:
Department of Geophysical Sciences, University of Chicago, 5734 S. Ellis Ave, IL 60637, USA
M. L. Rivers
Affiliation:
Department of Geophysical Sciences and Consortium for Advanced Radiation Sources, University of Chicago, 5734 S. Ellis Ave, Chicago, IL 60637, USA
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Abstract

In calcites and dolomites in seven African carbonatites, SrO, FeO and MnO occur in concentrations from 1 to 2 wt.%, whereas Ce, Y, Cu and Zn occur only at the ppm level. Sr, Ce and Y partition preferentially into calcite relative to co-existing dolomite, whereas Fe and Mn favour dolomite. Sr partitions preferentially into calcite relative to co-exisiting apatite, but the light rare-earth elements partition into apatite. Magnetite from Kerimasi contains up to 13 wt.% MgO and 6 wt.% MnO, extending the known ranges in composition of magnetites from carbonatites.

Keywords

mineral chemistrycarbonatitecarbonateapatitemagnetiteAfrica
Type
Mineralogy
Information
Mineralogical Magazine , Volume 60 , Issue 400 , June 1996 , pp. 415 - 425
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 1996

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