Alkaline Rocks and Carbonatites of the World

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Mutum

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Occurrence number: 
025-00-005
Country: 
Brazil
Region: 
Para
Location: 
Longitude: -57.42, Latitude: 1.88

Mutum is an approximately circular intrusion of 16 km2, part of which lies in Guyana, emplaced in basement rocks of the Guyana shield. It is composed principally of nepheline syenite containing perthite, some sodic plagioclase, abundant nepheline, cancrinite, carbonate, aegirine, sphene, apatite, fluorite and epidote. For the more extensive part of the complex lying in Guyana, see Muri complex and Twareitau (Guyana No. 3).

Economic: 
Rare earth phosphate minerals are present (Rodrigues and Lima, 1984).
Age: 
1026±28 Ma by K-Ar on feldspar (Issler et al. 1975; Oliveira et al. 1975.
References: 
ISSLER, R.S., LIMA, M.I.C. de, MONTALVAO, M.B.G. de and SILVA, G.G. da, 1975. Intrusivas feldspatoididas no Craton Guianes. Congresso Ibero-Americano de Geologia Economica, II: 363-82. OLIVEIRA, A. da S., FERNANDES, C.A.C., ISSLER, R.S., ABREU, A.S., MONTALVAO, R.M.G. de and TEIXEIRA, W. 1975. Folha NA.21 Tumucumaque e parte da Folha NB.21. DNPM Projeto Rodrigues and Lima, 1984.
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