stripes
The basaltic lavas and pyroclastic rocks of the Lemagrut and Oldeani volcanoes have not yet been differentiated by mapping; Lemagrut products also coalesce with those from Ngorongoro (No. 163-00-011). Although most of these rocks are basalts and olivine basalts, trachyte, phonolite and a little nephelinite have been identified in the south close to the shore of Lake Eyasi and also within the Lemagrut succession, and it is likely that more detailed work will identify further alkaline rocks. An analysis of trachyte from Lemagrut, including trace element and Sr, Nd and Pb isotope data, is in Paslick et al. (1995), and data on a phonolite 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.PASLICK, C., HALLIDAY, A.N., JAMES, D. and DAWSON, J.B. 1995. Enrichment of the continental lithosphere by OIB melts: isotopic evidence from the volcanic province of northern Tanzania. Earth and Planetary Science Letters, 130: 109-26.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.PICKERING, R. 1964. Endulen. Geological Survey of Tanzania, Quarter Degree Sheet, 52.
