Alkaline Rocks and Carbonatites of the World

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Volta Redonda


Occurrence number: 
Rio de Janeiro
Longitude: -44.08, Latitude: -22.55

A lava flow with a maximum thickness of 20 m outcrops over a semicircular area less than 1 km in diameter, 4.5 km southeast of Volta Redonda. It is associated with sediments of the Resenda Formation. The rock, provisionally classified as an ankaramite, consists of phenocrysts of titanaugite and olivine in a matrix of pyroxene, plagioclase, opaques, nepheline and analcime.

K-Ar on whole rocks gave 43.8±6.2 and 41.7±5.7 Ma (Riccomini et al. 1983).
C. B. Gomes, personal communication, 1985. RICCOMINI, C., MELO, M.S. de, CARNEIRO, C.D.R., ALMEIDA, F.F.M. de, MIOTO, J.A. and HASUI, Y. 1983. Sobre a occorencia de um derrame de ankaramito na bacia de Volta Redonda (RJ) e sua importancia na datacao das bacias tafrogenicas continentais do sudeste Brasileiro. Boletim de Resumos, Sociedade Brasileira de Geologia Nucleo de Sao Paulo, 4 Simposio Regional de Geologia: 23-4
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