A Discussion of Carbonatite Evolution and Nomenclature, and the Generation of Sodic and Potassic Fenites

A. R. Woolley
Department of Mineralogy, British Museum (Natural History), Cromwell Road, London SW7 5BD

Abstract: Possible evolutionary paths of alkali-rich carbonatite magma may be related to the production of sodic and potassic fenites. It is concluded that the latter are generated not from separate Na- and K-rich carbonatites, but by the earlier preferential loss of Na from a sodi-potassic carbonatite magma. Trends of both Fe and Mg enrichment in carbonatites are illustrated from a number of centres, and ascribed to crystal fractionation, although metasomatism may be partly responsible. Current nomenclature of carbonatites is unsatisfactory and a division into sövites, magnesiocarbonatites and ferrocarbonatites is proposed, based on rock chemistry.

Mineralogical Magazine; March 1982 v. 46; no. 338; p. 13-17; DOI: 10.1180/minmag.1982.046.338.03
© 1982, The Mineralogical Society
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