stripes
Jebel Ago is a dumbbell-shaped complex of 12x5 km which is probably formed of three concentric intrusions aligned north-south. It is intruded into basement complex rocks but a small patch of Nubian type sediments overlies the northern centre. Ago is composed of quartz syenite and granite with one sample from the middle ring being an olivine-bearing syenite. The rocks comprise perthite, quartz, which is about 10% in the northern part, more than this in the south but absent from the central ring, aegirine, augite and hornblende. Arfvedsonite is present in the southern part of the complex and the central syenite contains up to 10% of serpentinised olivine (J.R. Vail pers. comm., 2000; Hohndorf et al., 1994).
HOHNDORF, A., MEINHOLD, K-D. and VAIL, J.R. 1994. Geochronology of anorogenic igneous complexes in the Sudan: isotopic investigations in North Kordofan, the Nubian Desert and the Red Sea Hills. Journal of African Earth Sciences, 19: 3-15.J.R. Vail pers. comm., 2000.