Alkaline Rocks and Carbonatites of the World

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

Silaia (Silai, Gabal Salai)

stripes

Occurrence number: 
049-00-027
Country: 
Egypt
Location: 
Longitude: 34.87, Latitude: 24.05
Carbonatite: 
No

Peralkaline syenites and granites form a conspicuous hill 1.5 km in diameter, and there are a number of small stocks, of similar composition, to the southeast. The granites contain about 10% biotite together with aegirine-augite and sodic amphibole. Xenoliths of country rock are abundant in the outer part of the main intrusion. There are some aplitic dykes.

Age: 
A Rb-Sr isochron on four rocks gave 221±12 Ma (Hashad and El Reedy, 1979).
References: 

EL RAMLY, M.F., BUDANOV, V.I. and HUSSEIN, A.A.A. 1971. The alkaline rocks of south-eastern Egypt. Geological Survey of Egypt, Paper, 53: 1-111.HASHAD, A.H. and EL REEDY, M.W.M. 1979. Geochronology of the anorogenic alkalic rocks, South Eastern desert, Egypt. Annals of the Geological Survey of Egypt, 9: 81-101.

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