The General Geology of the Kruger National Park

Abstract

Geological units and new data gathered during regional mapping of the Kruger National Park are summarised. A simplified geological map is presented in conjunction with this paper. A large number of new geological formations have been recognised in the course of this regional mapping and new names have been proposed for these units. Some of these names have not yet been officially recognised by the South African Committee for Stratigraphy (SACS). On-going work by the Geological Survey and other organisations is likely to lead to further additions to and refinement of the data presented in this paper. The Goudplaats and Makhutswi Gneisses are the oldest rocks known in the park. They form the sialic basement of the various greenstone belts represented by the Murchison and Barberton sequences. The age relations of the Orpen Gneiss* have not yet been established. Tonalitic and trondjemitic gneisses constitute the first phase of intrusion of the Nelspruit Granite Suite. The Shamiriri, Macetse* and Baderoukwe Granites, and the Cunning Moor Tonalite* intrudes rocks of Swazian age during the succeeding Randian Erathem. At the commencement of the Mokolian Erathem syenite of the Phalaborwa Complex intruded the Makhutswi Gneiss. Subsequently extrusion of lavas and deposition of sediments of the Soutpansberg Group of Mokolian age took place in a fault-bounded trough in the northern part of the park. Diabase intruded the Group in the form of sills. Pre-Karoo dykes of various ages occur throughout the area. The Timbavati Gabbro represents the youngest Pre-Karoo intrusion. The Late Palaeozoic to Mesozoic Karoo Sequence extends from north to south along the eastern edge of the park and consists of sedimentary rocks overlain by basalt and rhyolite. The last phase of Karoo volcanism is represented by granophyre, gabbro and microgranite. The sedimentary Malvernia Formation of Cretaceous age unconformably overlies the basalt in the northern part of the park. Quarternary surficial deposits blanket the older rocks in places. * Not yet approved by SACS.