Quartz silt in mudrocks as a key to sequence stratigraphy (Kimmeridge Clay Formation, Late Jurassic, Wessex Basin, UK)
Sequence-stratigraphic interpretation of mudrocks is often carried out using proxy indicators for grain size or by consideration of other aspects of lithology thought to relate to sea-level change, such as organic-matter content. An alternative stratigraphic analysis, based on direct estimation of q...
| Main Authors: | , , , |
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| Format: | Journal article |
| Language: | English |
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2001
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| _version_ | 1797071081166602240 |
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| author | Williams, C Hesselbo, S Jenkyns, H Morgans-Bell, H |
| author_facet | Williams, C Hesselbo, S Jenkyns, H Morgans-Bell, H |
| author_sort | Williams, C |
| collection | OXFORD |
| description | Sequence-stratigraphic interpretation of mudrocks is often carried out using proxy indicators for grain size or by consideration of other aspects of lithology thought to relate to sea-level change, such as organic-matter content. An alternative stratigraphic analysis, based on direct estimation of quartz-silt content, was carried out on a major Late Jurassic mudrock (and oil source rock), the Kimmeridge Clay Formation of the Wessex Basin, Dorset, UK. The new data, generated by backscatter SEM, X-ray and image analysis, show decametre-scale stratigraphic patterns that are incompatible with many previous sequence-stratigraphic interpretations based on gamma-ray logs or visual lithofacies and biofacies description. Correlation with a basin-margin section in the Boulonnais, northern France, indicates that silt-rich intervals in basinal facies are coeval, within the limits of biostratigraphic resolution, with shallow-water sand-rich packages on the margin. Variation in silt content in the Kimmeridge Clay therefore appears to be a record of relative sea-level change of at least regional extent. It is suggested that analysis of silt content offers the most reliable basis for generation of a regional sequence stratigraphy in basinal mudrocks. A revised relative sea-level curve for the Wessex Basin Kimmeridgian and early Tithonian is presented based on this premise. |
| first_indexed | 2024-03-06T22:48:04Z |
| format | Journal article |
| id | oxford-uuid:5de2b48b-2b25-4fb6-ba35-b15097d4df91 |
| institution | University of Oxford |
| language | English |
| last_indexed | 2024-03-06T22:48:04Z |
| publishDate | 2001 |
| record_format | dspace |
| spelling | oxford-uuid:5de2b48b-2b25-4fb6-ba35-b15097d4df912022-03-26T17:36:59ZQuartz silt in mudrocks as a key to sequence stratigraphy (Kimmeridge Clay Formation, Late Jurassic, Wessex Basin, UK)Journal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:5de2b48b-2b25-4fb6-ba35-b15097d4df91EnglishSymplectic Elements at Oxford2001Williams, CHesselbo, SJenkyns, HMorgans-Bell, HSequence-stratigraphic interpretation of mudrocks is often carried out using proxy indicators for grain size or by consideration of other aspects of lithology thought to relate to sea-level change, such as organic-matter content. An alternative stratigraphic analysis, based on direct estimation of quartz-silt content, was carried out on a major Late Jurassic mudrock (and oil source rock), the Kimmeridge Clay Formation of the Wessex Basin, Dorset, UK. The new data, generated by backscatter SEM, X-ray and image analysis, show decametre-scale stratigraphic patterns that are incompatible with many previous sequence-stratigraphic interpretations based on gamma-ray logs or visual lithofacies and biofacies description. Correlation with a basin-margin section in the Boulonnais, northern France, indicates that silt-rich intervals in basinal facies are coeval, within the limits of biostratigraphic resolution, with shallow-water sand-rich packages on the margin. Variation in silt content in the Kimmeridge Clay therefore appears to be a record of relative sea-level change of at least regional extent. It is suggested that analysis of silt content offers the most reliable basis for generation of a regional sequence stratigraphy in basinal mudrocks. A revised relative sea-level curve for the Wessex Basin Kimmeridgian and early Tithonian is presented based on this premise. |
| spellingShingle | Williams, C Hesselbo, S Jenkyns, H Morgans-Bell, H Quartz silt in mudrocks as a key to sequence stratigraphy (Kimmeridge Clay Formation, Late Jurassic, Wessex Basin, UK) |
| title | Quartz silt in mudrocks as a key to sequence stratigraphy (Kimmeridge Clay Formation, Late Jurassic, Wessex Basin, UK) |
| title_full | Quartz silt in mudrocks as a key to sequence stratigraphy (Kimmeridge Clay Formation, Late Jurassic, Wessex Basin, UK) |
| title_fullStr | Quartz silt in mudrocks as a key to sequence stratigraphy (Kimmeridge Clay Formation, Late Jurassic, Wessex Basin, UK) |
| title_full_unstemmed | Quartz silt in mudrocks as a key to sequence stratigraphy (Kimmeridge Clay Formation, Late Jurassic, Wessex Basin, UK) |
| title_short | Quartz silt in mudrocks as a key to sequence stratigraphy (Kimmeridge Clay Formation, Late Jurassic, Wessex Basin, UK) |
| title_sort | quartz silt in mudrocks as a key to sequence stratigraphy kimmeridge clay formation late jurassic wessex basin uk |
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