High resolution stratigraphic analysis of turbidite system, Tanqua Karoo Basin, South Africa

The Tanqua submarine fan complex is located in the southwestern Karoo Basin of South Africa, and comprises four basin floor fans (Fans 1-4) and one slope fan (Fan 5). Fan 3 exhibits an extensively exposed turbidite system, which enables a detailed investigation of its architecture and growth history. A fan wide stratigraphic correlation has enabled the construction of a deterministic 3D fan model, illustrated by correlation panels and isopach maps. The stratigraphy of Fan 3 comprises 10 depositional units, interpreted as six sandy fan growth phases separated by four intervals of reduced deposition. The clinoformal geometry of the units defines Fan 3 as a prograding fan characterized by three depositional phases. The initial phase of turbidite sedimentation is represented by basal scours and deposition of thin-bedded channel-fill and sheet deposits. The second phase is characterized by widespread channeling, moderate overbank deposition and significant mid- and outer-fan construction. The final phase is marked by bypass of the proximal axial channel system, overbank aggradation and reduced progradation on the mid- and distal-fan. (C) 2003 Elsevier Science Ltd. All rights reserved.