Alkaline Rocks and Carbonatites of the World

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Barra Do Itapirapua

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Occurrence number: 
025-00-104
Country: 
Brazil
Region: 
Sao Paulo
Location: 
Longitude: -49.22, Latitude: -24.68

This carbonatite intrusion is situated only 2.3 km southeast of Itapirapua (No. 103) and forms a plug over 500 m high surrounded by precipitous cliffs; it is about 2 km2. The plug is emplaced in Precambrian Tres Corregos granites but talus-covered slopes conceal the contact, although fenitized granite occurs as loose blocks. The carbonatite is predominantly sovitic and shows fluidal and brecciated structures as well as feldspathic varieties. Rodrigues and Lima (1984) report the presence of baryte, synchisite, ancylite, melilite and pyrochlore in the carbonatite. Close to the eastern contact of the intrusion is a feldspathic carbonatite breccia with an iron-rich matrix and much fluorite and galena; there is widespread silicification of the carbonatite. Three small pipes of silicified carbonatite breccia have been mapped about 2 km east-southeast of the main plug.

Economic: 
REE-rich phosphates and carbonates occur and there is fluorite and galena mineralization.
References: 
D'ELBOUX, C.V., TAVARES, J.R.P. and PAIVA, I.B. 1982. Proposicao de modelo mineralizador basico-alcalino para pesquisa mineral na regiao meridional do escudo Precambriano Brasileiro. Anais Congresso Brasileiro de Geologia, 32(3): 1061-72. LAPIDO LOUREIRO, F.E. and TAVARES, J.R. 1983. Duas novas ocorrencias de carbonatitos: Mato Preto e Barra do Rio Itapirapua. Revista Brasileira de Geociencias, 13: 7-11. LAPIDO LOUREIRO, F.E. and TAVARES, J.R. 1983. Duas novas ocorrencias de carbonatitos: Mato Preto e Barra do Rio Itapirapua. Revista Brasileira de Geociencias, 13: 7-11
Fig. 219 The Itapirapua and Barra do Itapirapua intrusions (after D'Elboux et al. 1982, Fig. 3).
Scratchpads developed and conceived by (alphabetical): Ed Baker, Katherine Bouton Alice Heaton Dimitris Koureas, Laurence Livermore, Dave Roberts, Simon Rycroft, Ben Scott, Vince Smith