The Stukpan carbonatite in the Orange Free State Goldfield

Verwoerd W.J. ; Weder E.E.W. ; Harmer R.E. (1993)

The Stukpan Complex is interpreted to be an oval pipe-like body, 3.1 × 1.7 km in diameter, unconformably overlain by Karoo strata and a dolerite sill. One borehole penetrated an intrusive contact between fine-grained amphibole-rich calciocarbonatite and an alkaline amphibolite derived by fenitization from andesitic Ventersdorp lava. A second borehole encountered calciocarbonatite sills as well as red fenite and brecciated quartzite belonging to the Welkom Formation of the Central Rand Group. Geochemical logs show consistently high Sr contents in the carbonatite but low P, Nb, Zr, and REE. Despite erratic Cu and Ni values and sporadic sulphides no indications of economic mineralization have been found. Rb-Sr mineral separate geochronology yielded a well-constrained isochron age of 1354 ± 11 Ma for the carbonatite and confirmed a Ventersdorp (2700 Ma) age for the alkaline amphibolite. -from Authors

Please refer to this item in SUNScholar by using the following persistent URL:
This item appears in the following collections: