stripes
Mosonik is a deeply dissected volcano situated just west of the escarpment marking the western margin of the Gregory Rift and overlapping the rift valley faults. A crescent-shaped crater opens to the west, much of the western part of the volcano having been removed, probably by an explosive eruption. The volcano is built principally of nephelinite and phonolite lavas, but tuffs also occur. Ejected blocks include limestones and granite. There is a central approximately circular plug of sovite about 1 km in diameter and arcuate sovite dykes and irregular zones of carbonatite breccia occur, mainly to the south of the carbonatite plug (M.S. Garson, pers.comm. 1988). Whole rock analyses and Sr, Nd and Pb isotope data on three foidites, together with analyses of nepheline, titanite, magnetite and perovskite are in Paslick et al. (1996).
FOSTER, A., EBINGER, C., MBEDE, E. and REX, D. 1997. Tectonic development of the northern Tanzanian sector of the East African rift system. Journal of the Geological Society of London, 154: 689-700.M.S. Garson, pers. comm. 1988;
GITTINS, J. 1966. Summaries and bibliographies of carbonatite complexes. In: O.F. Tuttle and J. Gittins (eds), Carbonatites. 417-541. John Wiley, New York.
GUEST, N.J., JAMES, T.C., PICKERING, R. and DAWSON, J.B. 1961. Angata Salei. Geological Survey of Tanganyika, Quarter Degree Sheet, 39.
PASLICK, C., HALLIDAY, A.N., JAMES, D. and DAWSON, J.B. 1996. Indirect crustal contamination: evidence from isotopic and chemical disequilibrium in minerals from alkali basalts and nephelinites from northern Tanzania. Contributions to Mineralogy and Petrology, 125: 277-92.
