Abstract: Based on petrographic, mineralogical and geochemical data, two groups of rodingites have been documented from the polymetamorphic Vumba Schist Belt of Botswana. Group I rodingites contain relict chromite grains with zoned uvarovite-grossular + clinopyroxene + epidote/zoisite ± quartz, whereas group II rodingites contain no chromite and uvarovite. Although the presence of chromite with Cr/(Cr + Al + Fe3+) ratio > 90, similar to chromites found in komatiites, suggests a possible komatiitic origin of group I rodingites, the major and trace element chemical data of most analysed basic rocks from this belt indicate that the protoliths of both groups of rodingites are related to basalt/gabbro of komatiitic affinity. The rodingites formed during the M3 phase of metamorphism.
Mineralogical Magazine; September 1994 v. 58; no. 392; p. 375-386; DOI: 10.1180/minmag.1994.058.392.03
© 1994, The Mineralogical Society
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