Alkaline Rocks and Carbonatites of the World

Funded by HiTech AlkCarb - New geomodels to explore deeper for Hi-Tech critical raw materials in Alkaline rocks and Carbonatites

Erepecuru

stripes

Occurrence number: 
025-00-006
Country: 
Brazil
Region: 
Para
Location: 
Longitude: -55.67, Latitude: 1.08

This is a nearly circular intrusion some 2 km in diameter which is classified as part of the Uatuma Group igneous cycle (1900-1400 Ma). The principal rock type is a quartz syenite containing perthite, quartz, plagioclase (albite-andesine), hastingsitic amphibole, biotite, sphene, zircon, opaques, apatite and fluorite. Chemical analyses in Oliveira et al. (1975) indicate K2O>Na2O. It is only marginally alkaline.

Age: 
1806±69 Ma by Rb-Sr on syenite (Oliveira et al. 1975; Montalvao, 1976).
References: 
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. MONTALVAO, R.M.G. de, 1976. Esboco geologico-tectonico do Craton Guianes. Revista Brasileira de Geociencias, 6: 230-45
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