Reevaluating the process regime in the Sego Sandstone: Sedimentological and ichnological evidence for an underemphasised fluvial signature
Abstract Rocks of coastal to shallow‐marine origin are challenging to interpret owing to the complex interplay of various depositional processes. This study reevaluates the relative roles of fluvial, tidal and wave processes in the Upper Cretaceous Sego Sandstone (and subordinately in the underlying...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
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Wiley
2023-11-01
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| Series: | The Depositional Record |
| Subjects: | |
| Online Access: | https://doi.org/10.1002/dep2.245 |
| _version_ | 1797523743358058496 |
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| author | Marcello Gugliotta Daniel S. Collins James A. MacEachern Narjess El Euch‐El Koundi |
| author_facet | Marcello Gugliotta Daniel S. Collins James A. MacEachern Narjess El Euch‐El Koundi |
| author_sort | Marcello Gugliotta |
| collection | DOAJ |
| description | Abstract Rocks of coastal to shallow‐marine origin are challenging to interpret owing to the complex interplay of various depositional processes. This study reevaluates the relative roles of fluvial, tidal and wave processes in the Upper Cretaceous Sego Sandstone (and subordinately in the underlying Buck Tongue) of the Book Cliffs, USA, a well‐studied ancient coastal to shallow‐marine succession. Detailed sedimentological and ichnological analyses were used to interpret a previously underemphasised riverine signature, consisting of centimetre‐ to decimetre‐thick alternations of sandstone and heterolithic beds inferred to represent flood–interflood periods of variable river discharge. Recognition of a widespread fluvial‐dominated signature across the studied units better agrees with other sedimentological and regional observations in the study area, such as high sandstone–mudstone ratios, largely unidirectional and seaward‐oriented palaeocurrents, and modelled weak tidal conditions in the basin. When considering all of the sedimentological, ichnological and stratigraphic observations together with its regional depositional context, the Sego Sandstone/Buck Tongue system is better explained using a mixed‐energy but fluvial‐dominated deltaic model. This highlights an historical over‐interpretation of tidal processes and subordinate wave processes in the Sego Sandstone and likely in similar units. The widely used approach that emphasises only certain sedimentary features in discerning the process regime from analysis of rocks of inferred coastal to shallow‐marine origin is unrefined and may therefore underrepresent the actual complexity of these systems. |
| first_indexed | 2024-03-10T08:47:23Z |
| format | Article |
| id | doaj.art-026f1a88eeb144bcbed2b0ac8ae2e0f2 |
| institution | Directory Open Access Journal |
| issn | 2055-4877 |
| language | English |
| last_indexed | 2024-03-10T08:47:23Z |
| publishDate | 2023-11-01 |
| publisher | Wiley |
| record_format | Article |
| series | The Depositional Record |
| spelling | doaj.art-026f1a88eeb144bcbed2b0ac8ae2e0f22023-11-22T07:45:38ZengWileyThe Depositional Record2055-48772023-11-0194989100910.1002/dep2.245Reevaluating the process regime in the Sego Sandstone: Sedimentological and ichnological evidence for an underemphasised fluvial signatureMarcello Gugliotta0Daniel S. Collins1James A. MacEachern2Narjess El Euch‐El Koundi3Sedimentary Systems Research Group, Faculty of Geosciences University of Bremen Bremen GermanyShell International Ltd London UKARISE, Department of Earth Sciences Simon Fraser University Burnaby British Columbia CanadaSedimentary Basins and Petroleum Geology Laboratory, Department of Geology University of Tunis El Manar Tunis TunisiaAbstract Rocks of coastal to shallow‐marine origin are challenging to interpret owing to the complex interplay of various depositional processes. This study reevaluates the relative roles of fluvial, tidal and wave processes in the Upper Cretaceous Sego Sandstone (and subordinately in the underlying Buck Tongue) of the Book Cliffs, USA, a well‐studied ancient coastal to shallow‐marine succession. Detailed sedimentological and ichnological analyses were used to interpret a previously underemphasised riverine signature, consisting of centimetre‐ to decimetre‐thick alternations of sandstone and heterolithic beds inferred to represent flood–interflood periods of variable river discharge. Recognition of a widespread fluvial‐dominated signature across the studied units better agrees with other sedimentological and regional observations in the study area, such as high sandstone–mudstone ratios, largely unidirectional and seaward‐oriented palaeocurrents, and modelled weak tidal conditions in the basin. When considering all of the sedimentological, ichnological and stratigraphic observations together with its regional depositional context, the Sego Sandstone/Buck Tongue system is better explained using a mixed‐energy but fluvial‐dominated deltaic model. This highlights an historical over‐interpretation of tidal processes and subordinate wave processes in the Sego Sandstone and likely in similar units. The widely used approach that emphasises only certain sedimentary features in discerning the process regime from analysis of rocks of inferred coastal to shallow‐marine origin is unrefined and may therefore underrepresent the actual complexity of these systems.https://doi.org/10.1002/dep2.245Campaniancoastal to shallow‐marine systemsfluvial faciesprocess indicatorsriver dischargeWestern Interior Seaway |
| spellingShingle | Marcello Gugliotta Daniel S. Collins James A. MacEachern Narjess El Euch‐El Koundi Reevaluating the process regime in the Sego Sandstone: Sedimentological and ichnological evidence for an underemphasised fluvial signature The Depositional Record Campanian coastal to shallow‐marine systems fluvial facies process indicators river discharge Western Interior Seaway |
| title | Reevaluating the process regime in the Sego Sandstone: Sedimentological and ichnological evidence for an underemphasised fluvial signature |
| title_full | Reevaluating the process regime in the Sego Sandstone: Sedimentological and ichnological evidence for an underemphasised fluvial signature |
| title_fullStr | Reevaluating the process regime in the Sego Sandstone: Sedimentological and ichnological evidence for an underemphasised fluvial signature |
| title_full_unstemmed | Reevaluating the process regime in the Sego Sandstone: Sedimentological and ichnological evidence for an underemphasised fluvial signature |
| title_short | Reevaluating the process regime in the Sego Sandstone: Sedimentological and ichnological evidence for an underemphasised fluvial signature |
| title_sort | reevaluating the process regime in the sego sandstone sedimentological and ichnological evidence for an underemphasised fluvial signature |
| topic | Campanian coastal to shallow‐marine systems fluvial facies process indicators river discharge Western Interior Seaway |
| url | https://doi.org/10.1002/dep2.245 |
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