Structural tectonic evolution of the Buffels river shear zone, Namaqua sector, Namaqua-natal metamorphic province, South Africa

Abstract

The Buffels River shear zone is located in north-western Namaqualand within the Bushmanland Subprovince, approximately 50 km south of the town of Springbok in the Namaqua Metamorphic Province in South Africa. The Buffels River shear zone has an overall ENE-WSW orientation and spans approximately 95 kilometres from the West Coast belt to the Bushmanland plateau in the east where it is further masked by Cenozoic cover. The trace of the supracrustal belt is defined by a steep NNW-dipping, 4 km-wide zone consisting of mainly sheared supracrustal sequences and streaky augen gneiss which have a regionally consistent ENE-WSW trend of about 260°. The rocks of the supracrustal belt occur as sheet-like bodies generally concordant to the regional gneissic foliation and are bordered on either side by a wallrock of less deformed coarse-grained augen gneiss which has the same penetrative foliation trend as the supracrustal belt.