Stratigraphic and structural setting of the Griqualand West and the Olifantshoek Sequences at Black Rock, Beeshoek and Rooinekke Mines, Griqualand West, South Africa

The Black Rock to Rooinekke area has been influenced by the Kheis and Namaqua orogenies. Thrusting associated with the Kheis orogeny is well documented throughout the mining area. Thrusting at Rooinekke resulted in the Griqualand West Sequence rocks overlying parts of the Olifantshoek Sequence. At Black Rock lithologies of the Voelwater Subgroup have been thrusted onto the Olifantshoek Sequence. A prominent N-S trending graben structure has been observed in the Rooinekke, Beeshoek and Black Rock mining areas. The thrusts are disrupted by these N-S faults. At Rooinekke supergene replacement and enrichment of the iron ore is associated with pre-Olifantshoek N-S faulting. The Namaqua orogeny may also have played a part in upgrading the existing ore bodies under discussion.