Alkaline Rocks and Carbonatites of the World

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

Porto Das Caixas

stripes

Occurrence number: 
025-00-078
Country: 
Brazil
Region: 
Rio de Janeiro
Location: 
Longitude: -42.87, Latitude: -22.72
Carbonatite: 
No

A small intrusion of volcanic breccia cuts Tertiary sediments of the Barreiras Formation. It contains small alkaline rock fragments 1-10 mm in diameter in a phonolitic matrix of orthoclase, nepheline, cancrinite, pyroxene and secondary calcite.

References: 
LIMA, P.R.A. dos S. 1976. Geologia dos macicos alcalinos do estado do Rio de Janeiro. Semana de Estudos Geologicos, Itaguai: 205-59
Map: 
Fig. 1_204 Distribution of alkaline rocks around Rio de Janeiro.
Scratchpads developed and conceived by (alphabetical): Ed Baker, Katherine Bouton Alice Heaton Dimitris Koureas, Laurence Livermore, Dave Roberts, Simon Rycroft, Ben Scott, Vince Smith