Alkaline Rocks and Carbonatites of the World

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

Goedemoed (Robertson)

stripes

Occurrence number: 
151-00-042
Country: 
South Africa
Location: 
Longitude: 19.87, Latitude: -33.83
Carbonatite: 
No

There are three plugs of olivine melilitite in this area: Goedemoed, Goedvertrou and Sandvliet (Verwoerd et al., 1990). The Goedemoed plug is located 15 km southeast of Robertson. The rock consists of euhedral olivine phenocrysts (Fo82-87) and microphenocrysts of melilite, perovskite and titanomagnetite in a matrix of clinopyroxene, nepheline, titanomagnetite and rare biotite. Chemical and palaeomagnetic data on two specimens are given by Duncan et al. (1978).

Age: 
K-Ar gave 63.7±1.3 Ma (Duncan et al., 1987).
References: 

DUNCAN, R.A., HARGRAVES, R.B. and BREY, G.P. 1978. Age, palaeomagnetism and chemistry of melilite basalts in the southern Cape, South Africa. Geological Magazine, 115: 317-27.TALJAARD, M.S. 1937. South African melilite basalts and their relations. Transactions and Proceedings of the Geological Society of South Africa, 39: 281-316.VERWOERD, W.J., VILJOEN, J.H.A. and VILJOEN, K.S. 1990. Olivine melilitites and associated intrusives of the southwestern Cape province. Guidebook Geocongress ’90, Geological Society of South Africa, PR3: 1-60.

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