Alkaline Rocks and Carbonatites of the World

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

Kef Hahouner And Koudiat El Anzazza


Occurrence number: 
Longitude: 7.02, Latitude: 36.55

These are two lamproite intrusions of which Kef Hahouner is a steeply-dipping dyke-like body several 10s of metres thick which has been traced for about 1.2 km, and Koudiat el Anzazza, located 16 km to the east-northeast, a pipe some 100 m in diameter (Raoult and Velde, 1971; Kaminskey et al., 1993). The Kef Hahouner rock contains 5-25% olivine phenocrysts, which are generally altered but within fresh crystals are inclusions of pentlandite, chalcopyrite and Cr spinel. The matrix consists of sanidine, calcic plagioclase, a little salitic pyroxene, mica, apatite, xenocrysts of quartz, interstices of brown glass and secondary chalcedony and calcite. The Koudiat el Anzazza rock consists of olivine phenocrysts in a matrix of sanidine and glass with tiny grains of salite, pargasitic hornblende and mica; accessory garnet has been found. Three rock analyses, including a range of trace elements, are given by (Kaminskey et al., 1993) who consider that chemically they closely match the Spanish orendites and fortunites. However, the Algerian rocks are quartz normative and contain abundant Hy in the norm which suggests that their identification as lamproites is debatable.

The Kef Hahouner lamproite gave K-Ar dates of 9.3±0.5 and 10.9±0.5 Ma (Bellon and Brousse, 1977).
BELLON, H. and BROUSSE, R. 1977. Le magmatisme périméditerranéen occidental. Essai de synthèse. Bulletin de la Société Géologique de France, Ser 7, 19: 469-80.KAMINSKEY, F.V., RAMAN’KO, YE.F., KOLESNIKOV, S.K. and SALKHI, M. 1993. Lamproites of northern Algeria. International Geology Review, 35: 235-52.RAOULT, J.-F. and VELDE, D. 1971. Découverte de trachytes potassiques à olivine et d’andésites en coulées dans le Miocene continental au sud de Kef Hahouner (nord du Constantinois, Algérie). Comptes Rendus Hebdomadaires des Séances de L’Académie des Sciences, 272D: 1051-4.
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