Alkaline Rocks and Carbonatites of the World

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Mayo Darle (Mont De Guingues)

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Occurrence number: 
029-00-019
Country: 
Cameroon
Location: 
Longitude: 11.52, Latitude: 6.43

An elliptical complex of 12x5 km Mayo Darle is emplaced in Precambrian migmatitic gneisses and consists of granite, quartz syenite, granite porphyry and rhyolitic volcanic rocks which contain benmoreite xenoliths. The granites include both biotite- and sodic amphibole-bearing types which grade into each other. The amphibole is riebeckite and may co-exist with biotite or be the sole mafic phase.

Economic: 
Tin mineralization occurs in a stockwork of veins extending over 2.3 km2 with grades of 0.3% Sn. The mineralization is confined to biotite granites and vein minerals include quartz, cassiterite, zinnwaldite and minor topaz. Details of fluid inclusion studies are given by Nguere and Norman (1985).
Age: 
Rb-Sr dating of biotite from granite gave 56(8 and 65(12 Ma (Gazel et al., 1963). A whole rock Rb-Sr isochron on granite from Mayo Darle combined with granite from the nearby Mba Namboe intrusion gave 63.3(1.3 Ma (Lasserre, 1978). Cantagrel et al. (1978) report a K-Ar age on K-feldspar from granite of 49.5(1 Ma.
References: 
CANTAGREL, J.-M., JAMOND, C. and LASSERE, M. 1978. Le magmatisme alcalin de la ligne du Cameroun au Tertiaire inférieur: données géochronologiques K/Ar. Bulletin de la Société Géologique de France Compte Rendu Sommaire des Seances, 20: 300-3.GAZEL, J., LASSERRE, M., LIMASSET, J.-C. and VACHETTE, M. 1963. Ages absolus des massifs granitiques ultimes et de la minéralisation en étain du Cameroun. Comptes Rendus Hebdomadaires des Séances de L'Académie des Sciences. Paris, 256: 2875-8.KOCH, P. 1953. Notice explicative sur la feuille Banyo. Carte Geologique de Reconnaissance à l'échelle du 1/500,000. (E41) Territoire Cameroun. Paris.LASSERRE, M. 1978. Mise au point sur les granitoides dits "ultimes" du Cameroun: gisement, pétrographie et géochronologie. Bulletin du Bureau de Recherches Géologiques et Minières. Paris, IV: 143-59.NGUERE, F.R. and NORMAN, D.I. 1985. Mayo-Darle tin deposit, west-central Cameroon. 13th Colloquium of African Geology. St. Andrews, Scotland. Occasional Publication, International Center for Training and Exchanges in the Geosciences, 3: 302-3. (abstract)
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