Alkaline Rocks and Carbonatites of the World

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

Hadayib (Gebel Hadayib)


Occurrence number: 
Longitude: 33.55, Latitude: 23.13

Emplaced between Precambrian volcanic rocks and granites the intrusion comprises two structures, a southern ring and a northern centre which is larger and younger. The southern structure consists of an outer ring separated from an inner one by a wadi. Both rings are of syenites and quartz syenites with aegirine-augite and subordinate biotite. The topography suggests that the northern structure also forms a series of incomplete rings that consist of peralkaline syenites, similar to those of the southern structure, together with more peralkaline granites. The northern structure is partly overlain by volcanic rocks including 'trachybasalts', with plentiful aegirine-augite and amphibole, trachytes, and so-called dacites with some 20% prismatic aegirine-augite. The complex is cut by several microsyenite and quartz microsyenite dykes.


EL RAMLY, M.F., ARMANIOUS, L.K. and HUSSEIN, A.A.A. 1979. The two ring complexes of Hadayib and Umm Risha, SE. Desert. Annals of the Geological Survey of Egypt, 9: 61-9.

Fig. 3_55 Hadayib (after El Ramly et al., 1979, Fig. 2).
Scratchpads developed and conceived by (alphabetical): Ed Baker, Katherine Bouton Alice Heaton Dimitris Koureas, Laurence Livermore, Dave Roberts, Simon Rycroft, Ben Scott, Vince Smith