Assembly and break-up of the Kaapvaal Craton between 3.0 and 2.0 Ga – new constraints from the U-Pb-Hf detrital zircon record

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The Kaapvaal Craton (KC) in southern Africa contains a unique record of the Earth’s history over a period of nearly 2 billion years. It consists of an up to 45 km thick Archean basement made up of greenstones and granitoid rocks, the latter intruded during the successive amalgamation between 3.68 and 2.55 Ga. This basement is overlain by up to 10.000 m thick successions of sedimentary rocks, which were deposited in different basins mainly during three periods: group I at 3.5-3.2 Ga (sedimentary rocks in basins around the Barberton GSB, Swaziland, Limpopo Belt Central Zone); group II at 3.0-2.8 Ga (Witwatersrand and Pongola basins); group III at 2.65-2.08 Ga (Transvaal-Griqualand West basins, Limpopo Belt Central Zone). The sedimentary rocks of group I and II were deposited during the assembly of the KC accompanied by abundant granitoid intrusions, and those of group III during a period of magmatic quiescence. Consequently, detrital (magmatic) zircon grains in group I and II rocks have a great potential to provide detailed information about the amalgamation process of the KC, and those of group III about post-amalgamation processes, including information about an enigmatic hinterland, which supplied abundant zircon detritus during the Paleoproterozoic between 2.55 and 2.06 Ga. In this project, the amalgamation process of the proto-KC, as well as the nature of the enigmatic hinterland, its crustal evolution through time, and consequences for the late Archean to Paleoproterozoic continent reconstruction will be investigated by a systematic analysis of U-Pb-Hf isotopes and textures of detrital zircon grains in 25 key samples.