Poyatos-Moré, M, Jones, GD, Brunt, RL et al. (3 more authors) (2016) Mud-dominated basin margin progradation: processes and implications. Journal of Sedimentary Research, 86 (8). pp. 863-878. ISSN 1527-1404
Abstract
The accretion of coarse-grained material at the shelf-edge rollover has been emphasized in studies of basin margin progradation, despite fine grained sediment (clay and silt) representing a volumetrically more significant component of subaqueous clinothems. The timing and processes of fine-grained sediment transport across the shelf and onto the slope remains an understudied facet of sedimentary basin stratigraphy. Three exhumed basin margin-scale clinothems of the Permian Waterford Formation, in the Karoo Basin, South Africa, offer outcrop examples of margin development through the accretion of mud during flooded shelf conditions. The progradation of wave/storm-influenced sandy shelf topset deposits over a thick mudstone succession and beyond a previously established sand-rich shelf-edge rollover suggests that some periods of basin margin progradation took place exclusively via dilute mud-rich gravity flows. Detailed outcrop and core study of offshore mudstones reveals a high content of organic debris and mica. Individual beds show normal and inverse grading, internal erosion surfaces and moderate to low bioturbation, reflecting relatively stressed conditions in frequently supplied outer shelf to upper slope regions. The estimated low gradient (<0.7º) of the Karoo Basin margin and prevailing wave/storm conditions facilitated prolonged suspension of fluid mud and transport across the shelf and beyond the shelf-edge rollover in sediment gravity flows. This study represents a rare example of mudstone-dominated shelf-edge rollover deposits documented at outcrop and core, and demonstrates how fine-grained sediment accretion can play a significant role in basin margin progradation. Conventional depositional models do not adequately account for progradation of basin margins in the absence of sand supply, which implies potential risks in the identification of shelf edge rollover positions and application of trajectory analysis in strongly progradational margins.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © 2016, SEPM (Society for Sedimentary Geology). This is an author produced version of a paper published in Journal of Sedimentary Research. Uploaded in accordance with the publisher's self-archiving policy. |
Dates: |
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Institution: | The University of Leeds |
Academic Units: | The University of Leeds > Faculty of Environment (Leeds) > School of Earth and Environment (Leeds) > Institute for Applied Geosciences (IAG) (Leeds) |
Funding Information: | Funder Grant number Conoco Phillips Not Known BHP Petroleum (Americas) Inc SLOPE4 BP Egypt Company SLOPE4 Maersk Olie og Gas A/S MAERSK Statoil SLOPE4 Total Exploration & Production UK Ltd SLOPE4 Neptune Energy Norge AS (was VSG) SLOPE4 Operating Account OPERATING ACCOUNT |
Depositing User: | Symplectic Publications |
Date Deposited: | 08 Jul 2016 09:36 |
Last Modified: | 23 Jun 2020 15:34 |
Published Version: | https://dx.doi.org/10.2110/jsr.2016.57 |
Status: | Published |
Publisher: | Society for Sedimentary Geology (SEPM) |
Identification Number: | 10.2110/jsr.2016.57 |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:101873 |