Alkaline Rocks and Carbonatites of the World

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

Makonde (Ukisis)

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Occurrence number: 
163-00-043
Country: 
Tanzania
Location: 
Longitude: 34.52, Latitude: -10.05
Carbonatite: 
Yes

Little information is available on the Makonde carbonatite. A rock described as 'apatite limestone' by Haldemann and Harpum (1952) forms a conformable layer 7 m thick by 140 m long within gneiss. The rock consists of calcite, green apatite crystals of rounded outline up to 4 cm in length, abundant magnetite, sometimes in masses as much as 25 cm across, and a little olivine, partly altered to serpentine, and tremolite. An analysis of magnesiocarbonatite from Makonde is given by van Straaten (1989) and indicates >10,000 p.p.m. Sr, >1000 p.p.m. Ba and (Ce+Nd+La) = 1500 p.p.m. However, Nb is only 17 p.p.m.

References: 

HALDEMANN, E.G. and HARPUM, J.R. 1952. A preliminary account of the carbonate rocks of central Ukisi, Njombe District. Unpublished Report, Geological Survey of Tanganyika, 1-11.VAN STRAATEN, P. 1989. Nature and structural relationships of carbonatites from southwest and west Tanzania. In K. Bell (ed.) Carbonatites: genesis and evolution. 177-99. Unwin Hyman, London.

Scratchpads developed and conceived by (alphabetical): Ed Baker, Katherine Bouton Alice Heaton Dimitris Koureas, Laurence Livermore, Dave Roberts, Simon Rycroft, Ben Scott, Vince Smith