Alkaline Rocks and Carbonatites of the World

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

Tumbine (Milange)


Occurrence number: 
Longitude: 35.8, Latitude: -16.08

The almost circular intrusion of Tumbine has a diameter of 8 km and is expressed as the mountain of Serra Tumbine, which rises to 1542 m above a peneplain. The core of the intrusion consists of nepheline syenites which are surrounded by a ring of syenite. A sample of syenite described by Coelho (1959a) consists of perthite, biotite, aegirine-augite, with more sodic rims, riebeckite, scapolite and titanite. A second specimen has a gneissose fabric and consists of perthite, aegirine-augite, hornblende, biotite and a little riebeckite and apatite. Analyses of these two rocks indicate 7% and 14% normative nepheline, but quartz has been found in syenites close to the margins. A carbonatite is shown immediately southwest of Tumbine on Fig. 4.11.1 of Cilek (1989), but this may be an error.

Possible bauxite accumulations have been investigated but prove to be uneconomic (Cilek, 1989).
CILEK, V.G. 1989. Industrial minerals of Mozambique. Geological Survey, Prague. 326 pp.COELHO, A.V.P. 1959a. Reconhecimentos petrográficos sumários dos maciços da Lupata, Morrumbala, Chiperone-Derre e Milange. Boletim. Serviços de Geologia e Minas, Província de Moçambique, 26: 1-47.
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