Stratigraphic Prediction of Deepwater Clastic Systems Along the Exhumed 900 km Karoo/Falklands Basin Margin

PreviousNext You have accessInternational Conference and Exhibition, Melbourne, Australia 13-16 September 2015Stratigraphic Prediction of Deepwater Clastic Systems Along the Exhumed 900 km Karoo/Falklands Basin MarginAuthors: Stephen Flint*David HodgsonRufus BruntMiquel Poyatos-MoreStephen Flint*Stratigraphy Group, University of Manchester, Manchester, United KingdomSearch for more papers by this author, David HodgsonStratigraphy Group, University of Leeds, Leeds, United KingdomSearch for more papers by this author, Rufus BruntStratigraphy Group, University of Manchester, Manchester, United KingdomSearch for more papers by this author, and Miquel Poyatos-MoreStratigraphy Group, University of Manchester, Manchester, United KingdomSearch for more papers by this authorhttps://doi.org/10.1190/ice2015-2209228 SectionsAbout ToolsAdd to favoritesDownload CitationsTrack CitationsPermissions ShareFacebookTwitterLinked InRedditEmail Abstract A major exploration challenge is understanding along margin variability of broadly coeval deepwater systems in terms of geometry, architecture and net: gross. Many years of outcrop studies integrated with 20 fully cored research wells permits construction of a time-stratigraphic evolution of the NW-SE trending Permo-Triassic Karoo basin margin. Similar stratigraphy along the margin belies important differences in thicknesses, volumes and partitioning of sand between basin floor and submarine slope. A consistent hierarchy is applied based on depositional sequences that stack into composite sequences and composite sequence sets (CSS). The Tanqua Karoo depocentre includes 800 m of mudstone overlain by 4 basin floor fans, each 50 m thick with dip lengths of 40 km+, showing a progradational stacking pattern. The submarine slope section is 120 m thick, above which are shelf edge clinoforms and mixed influence deltas. Some 80 km along margin the 1200 m thick Laingsburg succession comprises distal basin plain turbidites punctuated by 3 mass transport complexes (MTCs). A 300 m+ basin floor fan composite sequence set is overlain by 3 further CCSs marking progradation of an 800 m thick muddy slope succession to the east with slope valleys feeding fan system 80-100 km long and up to 60 km3. Shelf edge clinoforms mark eastward progradation of a 500 m thick mixed influence delta system. 100 km east the margin is characterized by MTCs derived from a southern lateral slope, which alternate with undeformed 20-40 m thick lobe complexes. Overlying shelf deposits are sand-poor. 400 km east, the 1700 m Ecca Pass section includes a 300 m thick basin floor fan complex with no basal MTCs, overlain by a 100 m thick siltstone and slope channels. The shelf section is sand poor, suggesting a switch in sand delivery location between deepwater and shelf. The Falkland Islands lay 250 km east of Ecca Pass in the Permian and the 3 km+ succession is similar in terms of a basin floor fan complex with no MTCs and a 100 m siltstone cap, above which is 300 m of slope channel levee complexes with no slope valleys and a wave-dominated shelf succession. The exhumed Karoo-Falklands margin provides a well exposed example of lateral variability in basin margin physiography convolved with late icehouse to greenhouse transition glacio-eustatic sea level and long wavelength subsidence to control spatial and temporal variability in deepwater systems architecture and overlying shelf delta style. Keywords: deepwater, stratigraphy, progradationPermalink: https://doi.org/10.1190/ice2015-2209228FiguresReferencesRelatedDetails International Conference and Exhibition, Melbourne, Australia 13-16 September 2015ISSN (online):2159-6832Copyright: 2015 Pages: 564 publication data© 2015 Published in electronic format with permission by the Society of Exploration Geophysicists and the American Association of Petroleum GeologistsPublisher:Society of Exploration Geophysicists HistoryPublished Online: 16 Sep 2015 CITATION INFORMATION Stephen Flint*, David Hodgson, Rufus Brunt, and Miquel Poyatos-More, (2015), "Stratigraphic Prediction of Deepwater Clastic Systems Along the Exhumed 900 km Karoo/Falklands Basin Margin," SEG Global Meeting Abstracts : 84-84. https://doi.org/10.1190/ice2015-2209228 Plain-Language Summary KeywordsdeepwaterstratigraphyprogradationLoading ...