Palynostratigraphic correlation of the Springbok Flats coalfield to other coal-bearing successions in the Karoo basins of southern Africa

Abstract

Strata of the Springbok Flats, Ellisras and Tshipise (Soutpansberg-Pafuri) basins of South Africa are considered to have been deposited contemporaneously with those of the main Karoo Basin (MKB), but lithological differences complicate precise correlation. In this study, palynofloras from recently drilled boreholes in the Springbok Flats Basin (SFB) are used to correlate the Springbok Flats coal zones with other southern African coal-bearing successions. Permian palaeoenvironments of the SFB are reconstructed through a combination of palynology, sedimentology, and coal petrology. The lower coal zone (LCZ) palynoflora best correlates with Palynozone K4 in the MKB (equivalent to the Witbank No. 4 seam, Vryheid Formation) and can also be associated with Biozone D of the Waterberg Coalfield (Ellisras Basin), and the Vereeniging top seam in the New Vaal Colliery, northern Karoo Basin. The upper coal zone (UCZ) palynoflora of the SFB correlates closely with the Gwembe Formation (mid-Zambezi Basin, Zambia), Biozone E of the Waterberg Coalfield (Ellisras Basin), and Biozone KK 3 (Kalahari Karoo Basin, Botswana). A new radioisotopically constrained palynozonation for the MKB allows relative ages to be assigned to the coal zones of the SFB: Kungurian for the LCZ, and Roadian for the UCZ. Palynology is a useful tool in correlating these economically important strata across southern Africa.