Kattenhorn, S.A., Watkeys, M.K. (1995)


Some revelations from Karoo dolerite sills, west of Empangeni, KwaZulu-Natal.

Petros 14, 33-48.
(Note: This is a non-peer-reviewed article)

A study was undertaken of Karoo dolerite sills emplaced into Volksrust sediments west of Empangeni. This revealed that the sills injected an initial segmented fracture pattern involving both straight and curved fractures, with little overlap. Sill linkage was predominantly by simple inward curvature between adjacent offset sill segments that linked tip-to-tip. Sill dilation and magmatic flow features consistently indicate a magmatic flow direction to the north-north-east. During sill intrusion, the strain energy imposed on the host rock is calculated as 3.6 e10 N/m. The magma driving pressure, obtained by application of fracture mechanics equations, was about 2.0 - 4.7 e08 Pa, which was higher than the estimated overburden pressure. This suggests that extrusion of Karoo basalts had begun prior to emplacement of these particular sills.


Petros was a publication of the Students' Geological Society of the University of Natal (Durban), South Africa. It was published annually, and sometimes biennially, to publicize the current research being undertaken in the Department of Geology & Applied Geology at UND.



This paper has been cited in the following 2 works:

Uken, R., Watkeys, M.K., Reinhardt, J., 2005. Folding of the Rustenburg layered suite adjacent to the Steelpoort pericline: implications for syn-Bushveld tectonism in the eastern Bushveld Complex. SOUTH AFRICAN JOURNAL OF GEOLOGY 108 (3): 397-412.

Clarke, B.M., Uken, R., Watkeys, M.K., 2000. Intrusion mechanisms of the Southwestern Rustenburg Layered Suite as deduced from the Spruitfontein inlier. SOUTH AFRICAN JOURNAL OF GEOLOGY 103: 120-127.