Fig. 2

Geological map of the Karoo Basin with location of borehole KWV-1 (east of the town Willowvale, Eastern Cape Province; see Fig. 1), stratigraphic reference sections 1–3 (see Fig. 3) intersecting the Ripon Formation at depths >3000 m, seismic reflection profile a–a’ (Fig. 6), and stratigraphic log of KWV-1 (KO Koonap Formation, WF Waterford Formation, FB Fort Brown Formation, RP Ripon Formation, D Dolerite, WH Whitehill Formation, PA Prince Albert Formation, DG Dwyka Group), scale bars 350 m. Transparent rectangle west of East London marks the potential resource area. Transect A–C highlights the layer cake stratigraphy of the Karoo Basin with dolerite sills and dykes and location of borehole KWV-1 intersecting the uppermost Dwyka, entire Ecca, and lowermost Beaufort groups. Red dashed line marks the southern extent of dolerite intrusions (dolerite line; Veevers et al. 1994). Black dashed lines mark the craton boundaries of the Kaapvaal Craton (KC) in the north (Nguuri et al. 2001; James et al. 2003) and the Namaqua-Natal Metamorphic Belt (NNMB) in the south (Cornell et al. 2006) adjacent to the Cape Fold Belt, forming the basement of the Karoo Basin