stripes
Franz et al. (1993) describe briefly a province of igneous rocks extending over an area of 200x150 km on either side of the Nile in the vicinity of Delgo. These rocks mostly form isolated dykes and small intrusions of basalt, trachyte and phonolite with an area of ignimbrite extending over 12x7 km. In the southwest of the area a ring-shaped intrusion 3.5 km in diameter, Jebel Sheikh, consists of quartz syenite in the south, a central area of nepheline syenite and a northern part of microsyenite, trachyte and phonolite. There are ring- and radial dykes of rhyolite and trachyte.
FRANZ, G., HARMS, U., DENKLER, T. and PASTEELS, P. 1993. Late Cretaceous igneous activity in the Delgo uplift (Northern Province, Sudan). In U. Thorweihe and H. Schandelmeier (eds) Geoscientific Research in northeast Africa. 227-30. Balkema, Rotterdam.MULLER-SOHNIUS, D and HORN, P. 1994. K-Ar dating of ring complexes and fault systems in Northern Kordofan, Sudan: evidence for independent magmatic and tectonic activity. Geologische Rundschau, 83: 604-13.