Alkaline Rocks and Carbonatites of the World

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Rio Chirripo And Fila De Matama

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Occurrence number: 
039-00-003
Country: 
Costa Rica
Region: 
Limon and Cartago
Location: 
Longitude: -83.03, Latitude: 9.08

Along the northeastern side of the Cordillera de Talamanca, particularly on the Fila de Matama and in the Rio Chirripo, occur lavas of alkali basalt, basanite and nephelinite. The distribution is not known and no petrographic descriptions are available. The norm of a nephelinite (Robin and Tournon, 1978, Table 2, No. 1) includes Or, 5.56; Ab, 10.12; An, 16.75; Ne, 9.83; Di, 25.42 and Ol, 13.85, suggesting perhaps a basanite rather than a nephelinite.

Age: 
(?)Pliocene (Wadge and Wooden, 1982, Table 2).
References: 
ROBIN, C. and TOURNON, J. 1978. Spatial relations of andesitic and alkaline provinces in Mexico and Central America. Canadian Journal of Earth Sciences, 15: 1633-41. WADGE, G. and WOODEN, J.L. 1982. Late Cenozoic alkaline volcanism in the northwestern Caribbean: tectonic setting and Sr isotopic characteristics. Earth and Planetary Science Letters, 57: 35-46
Scratchpads developed and conceived by (alphabetical): Ed Baker, Katherine Bouton Alice Heaton Dimitris Koureas, Laurence Livermore, Dave Roberts, Simon Rycroft, Ben Scott, Vince Smith