Additional data on the geology of the Mbeya carbonatite

Abstract

Consists of an account of the geologic setting and age relations of the pyrochlore-bearing Mbeya carbonatite plug in southern Tanganyika (by van der Heyde) and discussion of the mode of emplacement of the plug, the character of associated dike and contact rocks, and the mineralogy of the carbonatite (by Fick). The main part of the intrusive mass is soevite, cut by numerous dolomitic, calcitic, and alvikitic dikes and surrounded by fenitized basement gneisses. Pyrochlore is most abundant in apatite-rich zones.