stripes
A steep-sided massif standing as much as 200 m above the surrounding recent sediment covered plains is composed of Precambrian basement gneisses into which a syenite intrusion of approximately 8x4 km is emplaced. It exhibits a series of semi-circular ring features which suggest a northwesterly progression of intrusion. The syenite consists of alkali feldspar, corroded fayalite, which is sometimes rimmed by biotite, and clinopyroxene which is usually zoned to more sodic rims or may be rimmed by calcic-sodic amphibole. Aenigmatite was identified in one sample. A smaller 2 km diameter intrusion of similar syenite lies 5 km to the southeast.
CURTIS, P. and BRINKMANN, K. 1985. The geology of younger intrusive alkali complexes in the southwestern Nuba Mountains, Sudan. Geologisches Jahrbuch, 63: 3-41.
