Eocene sequence stratigraphy of the North Sea Basin
Eocene elastic sediments of the central and northern North Sea comprise five stratigraphic sequences. Oldest is the sand-dominated, basin-centered Frigg sequence, which includes submarine fan and apron deposits on the Beryl Terrace and in the Central and Viking Grabens. Middle Eocene Lower and Upper...
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ftunivtexas:oai:repositories.lib.utexas.edu:2152/65019 2023-05-15T15:16:27+02:00 Eocene sequence stratigraphy of the North Sea Basin Sloan, Benjamin John Galloway, William E. Lagoe, Martin B. 1995 electronic application/pdf text/xml http://hdl.handle.net/2152/65019 https://doi.org/10.15781/T2HH6CP72 eng eng UT Electronic Theses and Dissertations doi:10.15781/T2HH6CP72 http://hdl.handle.net/2152/65019 Copyright © is held by the author. Presentation of this material on the Libraries' web site by University Libraries, The University of Texas at Austin was made possible under a limited license grant from the author who has retained all copyrights in the works. Open Geology Stratigraphic--Eocene Geology--North Sea Thesis 1995 ftunivtexas https://doi.org/10.15781/T2HH6CP72 2020-12-23T22:05:51Z Eocene elastic sediments of the central and northern North Sea comprise five stratigraphic sequences. Oldest is the sand-dominated, basin-centered Frigg sequence, which includes submarine fan and apron deposits on the Beryl Terrace and in the Central and Viking Grabens. Middle Eocene Lower and Upper Hordaland sequences are mixed mud and sand units which prograded from the East Shetland Platform and Moray Firth and include discrete slope aprons and basin-center fans. The thin, regressive sand-prone Belton sequence marks the top of the Eocene in most of the basin, except on the eastern margin of the Shetland Platform, where the foreshelf pro grading prism of Thet sequence sandstones and siltstones was deposited. Foraminiferal biofacies analysis of a well on the Beryl Terrace indicates that four or the five sequence boundaries coincide with significant changes in the benthic and planktic foraminiferal assemblages. Cluster analysis confirms the distinct biofacies characterizing each sequence, an impoverished coarsely agglutinated fauna with radiolaria in the Frigg sequence, normal abundances or coarsely agglutinated forms in the Hordaland units, and "Velasco"-type deep-water calcareous benthics in the Upper Eocene, including planktic foraminifera in the Belton. Paleoenvironmental analysis or these biofacies shows an overall Eocene shallowing from lower slope to outer shelf. Subsidence analysis using the derived water depths indicates that the Eocene was part or a major phase of subsidence which began in the Late Paleocene and abated by Oligocene time. Overall, the Eocene constitutes a tectonosequence, or stratigraphic sequence attributable to tectonic influences. Eocene circum-North Sea tectonics include Atlantic domain seafloor-spreading to the north and west and the encroaching Alpine compression from the south. The base Eocene, top Frigg, and top Eocene all correlate with changes in seafloor spreading thought to have contributed, through intraplate stresses, to the stress regime and differential topography of the source area and basin. Latest Eocene eustatic lowering, climatic cooling, and Arctic water circulation are thought to have influenced the Thet sequence. Geological Sciences Thesis Arctic Foraminifera* The University of Texas at Austin: Texas ScholarWorks Arctic |
institution |
Open Polar |
collection |
The University of Texas at Austin: Texas ScholarWorks |
op_collection_id |
ftunivtexas |
language |
English |
topic |
Geology Stratigraphic--Eocene Geology--North Sea |
spellingShingle |
Geology Stratigraphic--Eocene Geology--North Sea Sloan, Benjamin John Eocene sequence stratigraphy of the North Sea Basin |
topic_facet |
Geology Stratigraphic--Eocene Geology--North Sea |
description |
Eocene elastic sediments of the central and northern North Sea comprise five stratigraphic sequences. Oldest is the sand-dominated, basin-centered Frigg sequence, which includes submarine fan and apron deposits on the Beryl Terrace and in the Central and Viking Grabens. Middle Eocene Lower and Upper Hordaland sequences are mixed mud and sand units which prograded from the East Shetland Platform and Moray Firth and include discrete slope aprons and basin-center fans. The thin, regressive sand-prone Belton sequence marks the top of the Eocene in most of the basin, except on the eastern margin of the Shetland Platform, where the foreshelf pro grading prism of Thet sequence sandstones and siltstones was deposited. Foraminiferal biofacies analysis of a well on the Beryl Terrace indicates that four or the five sequence boundaries coincide with significant changes in the benthic and planktic foraminiferal assemblages. Cluster analysis confirms the distinct biofacies characterizing each sequence, an impoverished coarsely agglutinated fauna with radiolaria in the Frigg sequence, normal abundances or coarsely agglutinated forms in the Hordaland units, and "Velasco"-type deep-water calcareous benthics in the Upper Eocene, including planktic foraminifera in the Belton. Paleoenvironmental analysis or these biofacies shows an overall Eocene shallowing from lower slope to outer shelf. Subsidence analysis using the derived water depths indicates that the Eocene was part or a major phase of subsidence which began in the Late Paleocene and abated by Oligocene time. Overall, the Eocene constitutes a tectonosequence, or stratigraphic sequence attributable to tectonic influences. Eocene circum-North Sea tectonics include Atlantic domain seafloor-spreading to the north and west and the encroaching Alpine compression from the south. The base Eocene, top Frigg, and top Eocene all correlate with changes in seafloor spreading thought to have contributed, through intraplate stresses, to the stress regime and differential topography of the source area and basin. Latest Eocene eustatic lowering, climatic cooling, and Arctic water circulation are thought to have influenced the Thet sequence. Geological Sciences |
author2 |
Galloway, William E. Lagoe, Martin B. |
format |
Thesis |
author |
Sloan, Benjamin John |
author_facet |
Sloan, Benjamin John |
author_sort |
Sloan, Benjamin John |
title |
Eocene sequence stratigraphy of the North Sea Basin |
title_short |
Eocene sequence stratigraphy of the North Sea Basin |
title_full |
Eocene sequence stratigraphy of the North Sea Basin |
title_fullStr |
Eocene sequence stratigraphy of the North Sea Basin |
title_full_unstemmed |
Eocene sequence stratigraphy of the North Sea Basin |
title_sort |
eocene sequence stratigraphy of the north sea basin |
publishDate |
1995 |
url |
http://hdl.handle.net/2152/65019 https://doi.org/10.15781/T2HH6CP72 |
geographic |
Arctic |
geographic_facet |
Arctic |
genre |
Arctic Foraminifera* |
genre_facet |
Arctic Foraminifera* |
op_relation |
UT Electronic Theses and Dissertations doi:10.15781/T2HH6CP72 http://hdl.handle.net/2152/65019 |
op_rights |
Copyright © is held by the author. Presentation of this material on the Libraries' web site by University Libraries, The University of Texas at Austin was made possible under a limited license grant from the author who has retained all copyrights in the works. Open |
op_doi |
https://doi.org/10.15781/T2HH6CP72 |
_version_ |
1766346741026652160 |