Petrogenesis of the Tuli Basin high-Ti picrites and basalts, Karoo CFB, southern Africa: Classification, stratigraphy, emplacement, and mantle source heterogeneity

The Tuli Basin represents one of the larger erosional remnants of the rift-related sequences of the Karoo continental flood basalts (CFB) of southern Africa. We present previously unpublished bulk-rock major and trace element analyses for 787 high-Ti picrites and basalts, including both surface and drill core samples, as well as Sr-Nd-Hf-Pb-Os isotope compositions and rare earth element (REE) abundances for selected samples. Due to the identification of previously unrecognised basaltic sub-types, a new classification scheme for the high-Ti basalts and picrites of the Tuli Basin is proposed where they are divided into three types based on Zr/Nb and Ce/Y ratios: HZN-1, HZN-2, and LZN. The HZN-1 picrites/basalts occur at the base of the lava sequence and are overlain by the HZN-2 basalts, which, in turn, are overlain by the LZN basalts.