Alkaline Rocks and Carbonatites of the World

Setup during HiTech AlkCarb: an online database of alkaline rock and carbonatite occurrences

Sao Gotardo

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Occurrence number: 
025-00-063
Country: 
Brazil
Region: 
Minas Gerais
Location: 
Longitude: -46.1, Latitude: -19.35
Carbonatite: 
Yes

A suite of pebbles and cobbles of carbonatite and alkaline rocks, including pulaskite, urtite, melteigite and alkali gabbro, occur within conglomerates of the Cretaceous Uberaba Formation. They are thought to derive from an unknown intrusion, not those lying to the west, i.e. Tapira, Araxa, Salitre, Serra Negra and Catalao. The carbonatites consist of calcite, magnetite, apatite and pyrochlore and are quite different from the limestones of the local Bambui Group.

Age: 
78.2±4.0 Ma by K-Ar on pulaskite (Hasui and Cordani, 1968), which is the maximum age for the Uberaba Formation.
References: 

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.
HASUI, Y. and HASSANO, S. 1969. Indicio de um novo foco de rochas alcalinas em Sao Gotardo, Estado de Minas Gerais. Anais da Academia Brasileira de Ciencias, 41: 149-54

Scratchpads developed and conceived by (alphabetical): Ed Baker, Katherine Bouton Alice Heaton Dimitris Koureas, Laurence Livermore, Dave Roberts, Simon Rycroft, Ben Scott, Vince Smith