Alkaline Rocks and Carbonatites of the World

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

Morro Do Macaco (Ipora)


Occurrence number: 
Longitude: -51.05, Latitude: -16.42

This complex comprises a series of intrusions and associated volcanics forming a northwest-southeast-trending line over some 10 km. There are four distinct intrusions of peridotite with dunitic cores. These pass outwards into wehrlites, which in places then grade into olivine pyroxenites and clinopyroxenites. On the west of these bodies is an irregular intrusion of syenite bounded on its western margin by Devonian sandstones of the Furnas Formation. The syenite is nepheline-bearing and includes malignites and syenogabbros. There is also a little olivine gabbro. Areas of volcanic rocks were reported, but R. A. Fuck (personal communication to C. B. Gomes) says there are no volcanics, only dykes; these comprise phonolites, trachytes, tephrites, limburgites and nephelinites. Some fenitization occurs at the margin of the main intrusions.

DANNI, J.C.M. 1978. Magmatic differentiation of the alkaline-ultrabasic intrusions of the Ipora region, south west Goias, Brazil.In. Proceedings of the First International Symposium on Carbonatites, Pocos de Caldas: 149-67. FILHO, J.G.C.S. 1975. Carta Geologica do Brasil ao milionesimo. Folha Goiania SE.22. Texto Ecplicativo. Ministerio das Minas e Energia, Departamento Nacional da Producao Mineral. Brasilia. C. B. Gomes, personal communication, 1984.
Fig. 1_196 The Ipora Group of occurrences of alkaline intrusions of central Goias.
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