Origin and terminal architecture of a submarine slide: A case study from the Permian Vischkuil Formation, Karoo Basin, South Africa

Submarine mass movement deposits exposed in the Vischkuil Formation, Laingsburg Karoo Basin, South Africa, provide a rare opportunity to analyse and interpret their emplacement history and deformation processes at a scale comparable to seismic examples. An up to 80m thick slide deposit, continuously exposed in two 2km long sub-parallel sections, passes from extensionally deformed material (clastic dykes and down-dip facing low-angle shear surfaces) down-dip into a compressional toe zone with large (tens of metres amplitude) folds dissected by steep, up-dip facing thrust planes. The compressional shear planes sole out onto a highly sheared décollement and cross-cutting relationships indicate an up-depositional dip younging in the timing of fold dissection. Lithofacies characteristics and detailed correlation of volcanic ash and other marker beds over more than 500km2 in the bounding undeformed stratigraphy indicate a low-gradient (