stripes
The flows from the Gahinga volcano (3420 m) lying in Rwanda are sandwiched between the more extensive products of Muhabura and Sabinyo (No. 137-00-003) and, according to Antun et al. (1971), consist of absarokites, some of which tend towards banakite, kivite and trachyandesite. The rocks are described by Rogers et al. (1998), based on a total alkalis - silica diagram, as ranging from K-basalt and K-basanite through K-hawaiite and K-mugearite to K-benmoreite. They give nine rock analyses, including much trace element and Pb, Sr and Nd isotope data, and their brief petrographic description, given under Muhavura (No. 137-00-001), also applies to Gahinga.
ANTUN, P., BERTOSSA, A., DELHAYE, F., PEETERS, L., PETRICEC, V., SALEE, A. and WALEFFE, A. 1971. Carte géologique du Rwanda. Feulle Ruhengeri Nord (S2/29 NW et NE). 1:100,000. Institut Géographique Militaire de Belgique.DENAEYER, M-E. and SCHELLINCK, F. 1965. Recueil d’analyses des laves du fosse tectonique de l’Afrique Centrale. Annales, Museee Royal de l’Afrique Centrale, Tervuren, Belgique. Serie In 8°, Sciences Géologiques, 49: 1-234.ROGERS, N.W., JAMES, D., KELLEY, S.P. and MULDER, M. de 1998. The generation of potassic lavas from the eastern Virunga Province, Rwanda. Journal of Petrology, 39: 1223-47.
