Stratigraphic Evolution of Fine-Grained Submarine Fan Systems, Tanqua Depocenter, Karoo Basin, South Africa

• DOI: 10.2110/jsr.2006.03
• Publication Date: 2006-04-18T23:12:33Z
• Authors: D. M. Hodgson; S. S. Flint; D. Hodgetts; N. J. Drinkwater; E. P. Johannessen; S. M. Luthi
• Keywords: 14. Life underwater; 01 natural sciences; 0105 earth and related environmental sciences

Abstract The integration of correlated outcrop and newly acquired core wireline logs, extensive paleocurrent data, accurately mapped surfaces has enabled a common model the stratigraphic evolution to be developed four Permian fine-grained submarine fan systems (Fans 1–4) from Tanqua depocenter, SW Karoo Basin, South Africa. Additionally, this data revealed influence subtle seabed topography on systems' boundaries, internal facies architecture, directions. Furthermore, stratigraphy individual are now known more complex than first believed. Mapping high-frequency intrafan units reveals progradational–aggradational–retrogradational stacking pattern each fan, which allows geographic distribution lithofacies architectural elements predicted. Basinward main feeder system, axes dominated architecturally by sheet turbidites with discrete zones high amalgamation during progradational aggradational phases, whereas isolated channel forms that cut thin-bedded in retrogradational phase. This change is interpreted due local increase lower slope gradient through sediment aggradation increasing potential for avulsion development splay lobes decreasing supply. progradational, aggradational, phases assigned early, middle, late lowstand tract fifth-order sequence respectively. Each phase built higher-frequency (sixth-order) sequences so composite sequence. overall basinward-to-landward stepping fans means moving down dip any basin-floor lowermost sandstone preserved progressively younger, whilst uppermost older. imparts an important predictable control reservoir seal geometries. study aids predictive models initiation, growth, abandonment, element distributions space time.