stripes
Jebel Katul forms a hill rising from a plain of superficial soils and clays. An approximately circular area some 10 km in diameter is underlain by flow-banded lavas, tuffs, agglomerates and breccias of rhyolitic composition. Phenocrysts of quartz and alkali feldspar lie in a matrix in which needles of riebeckite are abundant, often as radial growths around phenocrysts or in spherulites. The narrow boulder-strewn ridge of Jebel El Meitan extends east-northeastwards from Katul and is composed of syenite, which is chilled against lavas, and contains rare sodic pyriboles and a little quartz. An outlier, Jebel Abu Asal, lies about 14 km from Katul. The outcrop covers about 3x4 km and consists principally of acid volcanic rocks with quartz syenites, containing aegirine and riebeckitic amphiboles, on the flanks (J.R. Vail, pers. comm., 2000)
DELANEY, F.M. 1958. Observations on the Sabaloka series of the Sudan. Transactions of the Geological Society of South Africa, 61: 111-24.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.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.J.R. Vail, pers. comm., 2000.