Alkaline Rocks and Carbonatites of the World

Setup during HiTech AlkCarb: an online database of alkaline rock and carbonatite occurrences

Jebel Sileitat And Jebel Es Sufra

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Occurrence number: 
155-00-055
Country: 
Sudan
Location: 
Longitude: 32.7, Latitude: 15.88
Carbonatite: 
No

Jebel Sileitat stands as an inselberg above a surrounding plain of Nubian Sandstone which separates it from Jebel es Sufra to the north. The rock is a granite with pegmatitic streaks which passes upwards on some ridges into rhyolite; felsite dykes occur. All rock types contain riebeckite, and some varieties of granite a pale green pyroxene. South of Jebel es Sufra exposures of pyroclastic rocks consist of large boulders of riebeckite-bearing granite and rhyolite in a coarse rhyolitic tuff.

Age: 
A K-Ar age determination on a whole rock sample of granite gave a minimum age of 165 Ma (Brook and Rundle, 1974). Klemenic (1983) obtained a Rb-Sr age of 169±2 Ma.
References: 

AHMED, F. 1977b. The Sileitat-es-Sufur subvolcanic intrusion, northern Kordofan Province. Sudan Notes and Records, 58: 226-33.BROOK, M. and RUNDLE, C.C. 1974. K:Ar age determinations on whole rock specimens from northern Sudan. Report, Isotopic Geology Unit, Institute of Geological Sciences, London, 74.2: 1-4.DELANEY, F.M. 1958. Observations on the Sabaloka series of the Sudan. Transactions of the Geological Society of South Africa, 61: 111-24.KLEMENIC, P.M. 1983. Isotope geology and geochemistry of selected igneous complexes and basement rocks in north-east Sudan. Ph.D. thesis, Portsmouth Polytechnic. 385 pp. (unpublished).

Location: 
Scratchpads developed and conceived by (alphabetical): Ed Baker, Katherine Bouton Alice Heaton Dimitris Koureas, Laurence Livermore, Dave Roberts, Simon Rycroft, Ben Scott, Vince Smith