The Kalahari Craton, Southern Africa: From Archean crustal evolution to Gondwana amalgamation

Abstract

The Kalahari Craton comprises all Archean to Mesoproterozoic rocks of southern Africa, which are surrounded by Pan-African orogenic belts that resulted from the amalgamation of Gondwana. Progressive crustal growth and accretion of minor crustal blocks is recorded during the Archean and also involved reworking of Hadean crustal remnants, suggesting modern plate tectonics was already operating in the late Neoarchean. The first widespread Paleoproterozoic tectonomagmatic event is recorded by intracontinental magmatism of the Bushveld Complex and the Okwa Terrane and coeval magmatism in the Limpopo Belt, which separates the Archean Kaapvaal and Zimbabwe cratons. Afterwards, Paleoproterozoic transpression took place along the Limpopo Belt and was contemporaneous with the Magondi Orogeny. Subsequent addition of juvenile Paleoproterozoic crust took place along the western margin of the proto-Kalahari margin, as recorded by the Rehoboth Basement Inlier. During the Mesoproterozoic, subduction zones were present all around the Archean-Paleoproterozoic proto-Kalahari Craton. The accretion of several microcontinents and island arcs along the southern margin gave rise to the Namaqua-Natal Orogeny. Tonian to Cryogenian intraplate magmatism was finally succeeded by the incorporation of the Kalahari Craton into Gondwana during the protracted late Neoproterozoic-early Paleozoic Pan-African Orogeny.