Alkaline Rocks and Carbonatites of the World

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Catalao I

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Occurrence number: 
025-00-056
Country: 
Brazil
Region: 
Goias
Location: 
Longitude: -47.83, Latitude: -18.13

Catalai I is an approximately circular complex covering 27 km2 and lying 15 km south of Catalao II. It is emplaced in mica schists and quartzites of the Precambrian Araxa Super Group, which it fenitizes. Extensive drilling has indicated that a carbonatitic core is surrounded by pyroxenites, serpentinized peridotites and glimmerites. The pyroxenite-peridotite-glimmerite series comprises various combinations of phlogopite, serpentine, olivine, carbonates, amphibole, pyroxene, feldspar, magnetite, apatite and occasionally zircon, sphene and nepheline. A little nepheline syenite has been found. The carbonatites appear to comprise an earlier series of phlogopite carbonatites containing a broad range of accessory minerals, which are cut by veins of beforsite and sovite with many accessories including monazite, perovskite, baryte and pyrochlore. There are late silexite veins throughout the intrusion. In an aureole of fenites 300-500 m wide Na- and K-feldspars, aegirine and sodic amphibole have developed in schists and quartzites.

Economic: 
Mineralized zones enriched in phosphate, Nb, Ti, REE and vermiculite have been delimited (Carvalho and Araujo, 1974) and details of estimated reserves are given by Carvalho (1974b). Niobium deposits have been worked since 1976 and yield about 4000 tons annually of Ce-bariopyrochlore concentrates. Secondary phosphate deposits (carbonate-apatite) have also been developed, production starting in 1979.
Age: 
K-Ar on alkali syenite gave 82.9±4.2 Ma (Hasui and Cordani, 1968, Table 1).
References: 
CARVALHO, W.T. de, 1974a. Aspectos geologicos e petrograficos do complexo ultramafico-alcalino de Catalao I, Go. Anais Congresso Brasileiro de Geologia, 28: 107-23. CARVALHO, W.T. de, 1974b. Recursos minerais do complexo ultramafico-alcalino de Catalao I, Go. Anais Congresso Brasileiro de Geologia, 28: 165-84. CARVALHO, W.T. de and ARAUJO, P.L. de, 1974. Perspectivas de aproveitamento economico dos depositos minerais associados ao complexo ultramafico-alcalino do Catalao I, Go. Anais Congresso Brasileiro de Geologia, 28: 131-9. GASPAR, J.C. and ADUSUMILLI, M.S. 1976. Sobre os carbonatos do complexo Catalao I, Go. Boletim Mineralogico, Recife, 4: 5-22. HASUI, Y. and CORDANI, U.G. 1968. Idades potassio-argonio de rochas eruptivas Mesozoica do oeste mineiro e sul de Goias. Anais Congresso Brasileiro de Geologia, 22: 139-43
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