Alkaline Rocks and Carbonatites of the World

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Kapsikis Plateau

stripes

Occurrence number: 
030-00-004
Country: 
Cameroon
Location: 
Longitude: 13.62, Latitude: 10.53

Numerous plugs, small domes and flows are cut and overlie the metamorphic rocks of the Kapsikis Plateau and, according to Gouhier (1978), these form lines along two directions. The plugs are often deeply eroded to form spectacular spines up to 100 m high. Basalt, trachyte and rhyolite are represented, the olivine basalts forming extensive flows and small domes whereas the more evolved rocks form plugs. Four types of trachyte are distinguished by Gouhier (1978) namely biotite, quartz-aegirine, quartz-amphibole and alkaline trachytes, the last consisting essentially of phenocrystal and groundmass sanidine. The quartz-amphibole trachytes also contain aegirine and the amphibole is probably arfvedsonite. Rhyolites may either be cryptocrystalline with mineral phases difficult to distinguish or quartzphyric with acicular riebeckite present as globular structures. Four rock analyses are given by Gouhier (1978).

Age: 
K-Ar on a basalt gave 27.4±0.5 Ma and on trachyte 29.6±0.6 Ma (Gouhier et al., 1974).
References: 
GOUHIER, J. 1978. Le volcanisme des Kapsikis et ses relations avec la tectonique du socle au Cameroun. Annales de la Faculté des Sciences de Yaoundé, Université de Yaoundé, Yaoundé, 25: 69-78. GOUHIER, J., NOUGIER, J. and NOUGIER, D. 1974. Contribution à l'étude volcanologique du Cameroun ("Ligne du Cameroun" - Adamaoua). Annales de la Faculté des Sciences, Université du Cameroun, Yaoundé, 17: 3-48.
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