Alkaline Rocks and Carbonatites of the World

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Taourirt Area

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Occurrence number: 
113-00-002
Country: 
Morocco
Location: 
Longitude: 3.1, Latitude: 34.42

In the vicinity of Taourirt dykes and sills, up to three metres thick, and a number of breccia pipes comprise rocks which were originally called aiounite and mestigmerite (see Jérémine, 1948 and Cherotzky, 1967) the former being described as ferromagnesian-rich rocks of augite, biotite and opaques in a poorly defined groundmass and the latter as ferromagnesian-poor rocks characterised by the presence of 'acmitic augite', nepheline and accessory apatite and titanite. Mokhtari and Velde (1988) refer to those in the vicinity of Ferme Dubois as camptonites. Two types are distinguished by Mokhtari and Velde (1988), one containing phlogopite the other kaersutite; the other major phases are clinopyroxene, which extends from ferrosalite to aegirine, and kaersutite with late hastingsitic amphiboles. Feldspar, and possible nepheline, have generally been altered to zeolite but rare fresh material consists of co-existing plagioclase and alkali feldspar. Jérémine (1948) describes examples of these rocks rich in nepheline and these may be melteigites, Lacroix (quoted in Jérémine, 1948) apparently considering them to be fasinites. Titanomagnetite is common, mica occurs in the matrix and olivine (Fo81-85), hauyne and perovskite are found in some varieties. Wagner et al. (1993) have investigated an olivine nephelinite from the area which contains xenocrystic potassic richterite, and Mokhtari and Velde (1988) describe a suite of xenocrysts which include spinel, clinopyroxene, including Cr-bearing diopside, several types of mica and amphibole. A calcite carbonatite inclusion 20 cm in diameter, found in a camptonite, has been described by Mokhtari et al. (1996). It comprises Sr-rich calcite (2.8% SrO), pyrochlore, fluorapatite and rare salite; mineral and whole rock analyses are given. The extent of this locality is not clear from the literature consulted and it probably contains a broader range of rock types than described here, but a full general account has not been located.

Age: 
K-Ar on biotite from aiounite gave 37(6 and 57(3 Ma (Charlot et al., 1964).
References: 
AGARD, J. 1950. Sur l'âge le mode de gisement des aïounites et mestigmerites du Maroc Oriental. Notes et Mémoires. Service Géologique Maroc, 76(3): 189-95.CHARLOT, R., CHOUBERT, G., FAURE-MURET, A and HAMEL, C. 1964. Age des aïounites du Maroc nord-oriental. Compte Rendu Sommaire des Séances de la Société Géologique de France, 401-2.CHEROTZKY, G. 1967. À propos de la composition chimique des mestigmerites et aïounites. Mines et Géologie. Royaume du Maroc, Ministere du Commerce, de l’Artisanat, de l’Industrie et des Mines. Rabat, 25: 51-6.JÉRÉMINE , E. 1948. Sur quelques roches provenant du Maroc Oriental aïounite and mestigmerite. Notes et Mémoires. Service Géologique Maroc, 71(1): 67-71.MOKHTARI, A. and VELDE, D. 1988. Xenocrysts in Eocene camptonites from Taourirt, northern Morocco. Mineralogical Magazine, 52: 587-601.MOKHTARI, A., WAGNER, C. and VELDE, D. 1996. Découverte d’une enclave de carbonatite dans une camptonite de la region de Taourirt (Nord-est du Maroc). Conséquences géologiques. Comptes Rendus de l’Académie des Sciences, Paris. Sciences de la Terre et des Planètes, Ser 2, 323: 467-74.WAGNER, C., MOKHTARI, A. and VELDE, D. 1993. Xenocrystic richterite in an olivine-nephelinite: destabilisation and diffusion phenomena. Mineralogical Magazine, 57: 515-25.
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