Boulesteix, K, Poyatos‐Moré, M, Flint, SS et al. (3 more authors) (2019) Transport and deposition of mud in deep‐water environments: Processes and stratigraphic implications. Sedimentology, 66 (7). pp. 2557-3064. ISSN 0037-0746
Abstract
Deep-water mudstones are often considered as background sediments, deposited by vertical suspension fallout, and the range of transport and depositional processes are poorly understood compared to their shallow-marine counterparts. Here, we present a dataset from a 538.50 m-thick cored succession through the Permian muddy lower Ecca Group of the Tanqua depocentre (southwest Karoo Basin, South Africa). This study aims to characterize the range of mudstone facies, transport and depositional processes, and stacking patterns recorded in deep-water environments prior to deposition of the Tanqua Karoo sandy basin-floor fans. A combination of macroscopic and microscopic description techniques and ichnological analysis has defined nine sedimentary facies that stack in a repeated pattern to produce 2–26-m-thick depositional units. The lower part of each unit is characterized by bedded mudstone deposited by dilute, low-density turbidity currents with evidence for hyperpycnal-flow processes and sediment remobilization. The upper part of each unit is dominated by more organic-rich 27 bedded mudstone with common mudstone intraclasts, deposited by debris flows and transitional flows, with scarce indicators of suspension fallout. The intensity of bioturbation and burrow size increases upward through each depositional unit, consistent with a decrease in physicochemically stressed conditions, linked to a lower sediment accumulation rate. This vertical facies transition in the single well dataset can be interpreted to represent relative sea level variations, where the hyperpycnal stressed conditions in the lower part of the units were driven by sea level fall and the more bioturbated upper part of the unit represents backstepping, related to sea level rise. Alternatively, this facies transition may represent autogenic compensational stacking. The prevalence of sediment density flow deposits, even in positions distal or lateral to the sediment entry point, challenges the idea that deep-water mudstones are primarily the deposits of passive rainout along continental margins.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © 2019 The Authors. Sedimentology © 2019 International Association of Sedimentologists. This is the post-peer reviewed version of the following article: , Boulesteix, K, Poyatos-More, M, Flint, SS et al. (3 more authors) (2019) Transport and Deposition of Mud in Deep-water Environments: Processes and Stratigraphic Implications. Sedimentology, which has been published in final form at https://doi.org/10.1111/sed.12614. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions. |
Keywords: | Deep‐water; depositional processes; Karoo Basin; mudstone; Permian; trace fossils; turbidite |
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 Statoil SLOPE4 Total E&P UK Ltd SLOPE4 BHP Petroleum (Americas) Inc SLOPE4 BP Egypt Company SLOPE4 Maersk Olie og Gas A/S MAERSK Neptune Energy Norge AS (was VSG) SLOPE4 |
Depositing User: | Symplectic Publications |
Date Deposited: | 01 Apr 2019 11:01 |
Last Modified: | 08 Apr 2020 00:38 |
Status: | Published |
Publisher: | Wiley |
Identification Number: | 10.1111/sed.12614 |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:144280 |