Palaeomagnetic results from the Timbavati gabbros in the Kruger National Park, South Africa

The Timbavati Gabbros are an extensive group of basic intrusives which crop out over 200 km in the northeastern part of South Africa; published radiometric ages range from 1072 ± 4 Ma (⁴⁰Ar/ ³⁹Ar) to 1454 ± 50 Ma (Rb-Sr). Oriented samples were collected from six sites and results from an additional site sampled by Henthorn (1981) have been incorporated. Five of the sites yielded consistent mean magnetization directions from which a (reversed) palaeomagnetic pole was calculated at 63.2°N, 46.8°E, k = 533, α = 3.3°. This pole coincides closely with others obtained from coeval basic igneous rocks in Zimbabwe, Botswana, and elsewhere in South Africa, confirming the wide areal extent (~1200 × 800 km) of the ~1100 Ma Umkondo igneous event. A mean pole calculated from five separate studies of these intrusives lies at -65.4N, 36.1E, α = 6.5°. -Authors