Fossil woods of Karoo age deposits in South Africa and Namibia as an aid to biostratigraphical correlation

The Karoo Basin extended from South Africa, through Namibia, into adjacent southeastern South America during the Palaeozoic. Sedimentation in differen t parts of the basin varied in depth and duration, so attempts have been ma de to correlate the smaller basins within the whole region. Vertebrate foss ils are rare in Namibia, as are good macroplants, but fossil wood is abunda nt. Samples have been collected from the Tsarabis, Huab and Gai As Formatio ns and the Krone Member of the Etjo Sandstone Formation from several locali ties. The woods have been identified and correlated with woods from known b iozones from the main South African Karoo Basin. Based on the wood the Tsar abis Formation is equivalent to the Ecca and Beafort Groups (Permian: Proto taxoxylon africanum, Araucarioxylon africanum and Araucarioxylon karooensis ). The Huab Formation is equivalent to the Upper Beaufort Group (Permo-Tria ssic: Protopodocarpoxylon sp., A. africanum). The Gai As Formation has wood s of the Upper Beaufort and even the Jurassic (Permo-Triassic-Jurassic?: Pr otopodocarpoxylon of. P. lamtharii, Protopinaceae, A. africanum). An altern ative interpretation is that the Protopinaceae evolved earlier than the Jur assic in Namibia. The wood from the Krone Member (A. karooensis) occurs in the South African Upper Beaufort so the range of this wood should be extend ed. More woods need to be examined to confirm this preliminary biostratigra phy and it needs to be further tested with other fossil data. The boundarie s between the formations cannot be determined by the woods. (C) 2000 Elsevi er Science Limited. All rights reserved.