stripes
The Sabinyo volcano rises to 3590 m and is sandwiched between Gahinga (No. 137-00-002) and Visoke (No. 137-00-004). The lavas are indicated on the map of Antun et al. (1971) as comprising latite, kivite tending to ugandite and minor absarokite; one kivite flow extends some 24 km further south than any other flows from Sabinyo or the adjacent volcanoes. However, exposure of the Sabinyo lavas is poorer than that of the adjacent volcanoes because they are widely covered by breccia and sedimentary deposits. It is different from all the other volcanoes of the Virunga field in that its lavas are silica-saturated, orthopyroxene-bearing K-trachyte and latite (Rogers et al., 1998). They are porphyritic rocks of orthopyroxene, K-feldspar and clinopyroxene with phenocrysts, or xenocrysts (?), of mica and amphibole; olivine and feldspathoid are notable by their absence. Two shoshonites from Sabinyo are given in the compilation of rock analyses of Denaeyer and Schellinck (1965) and Rogers et al. (1971) give six rock analyses, including much trace and Pb, Sr and Nd isotope data.
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.
