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| Titel |
Mapping the North Sea base-Quaternary: using 3D seismic to fill a gap in the geological record |
| VerfasserIn |
Rachel Lamb, Mads Huuse, Margaret Stewart, Simon H. Brocklehurst |
| Konferenz |
EGU General Assembly 2014
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 16 (2014) |
| Datensatznummer |
250086857
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| Publikation (Nr.) |
 EGU/EGU2014-791.pdf |
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| Zusammenfassung |
| The identification and mapping of the base-Quaternary boundary in the central
parts of the North Sea is problematic due to the change from an unconformable
transition between Pliocene and Pleistocene deltaic deposits in the southern North
Sea to a conformable one further north (Sejrup et al 1991; Gatliff et al 1994). The
best estimates of the transition use seismic reflection data to identify a ‘crenulated
reflector’ (Buckley 2012), or rely on correlating sparse biostratigraphy (Cameron et
al 1987). Recent integration of biostratigraphy, pollen analysis, paleomagnetism
and amino acid analysis in the Dutch and Danish sectors (Rasmussen et al 2005;
Kuhlmann et al 2006) allows greater confidence in the correlation to a regional 3D
seismic dataset and show that the base-Quaternary can be mapped across the entire
basin.
The base-Quaternary has been mapped using the PGS MegaSurvey dataset from wells in
the Danish Sector along the initially unconformable horizon and down the delta front into the
more conformable basin giving a high degree of confidence in the horizon pick.
The mapped horizon is presented here alongside the difference between this new
interpretation and the previously interpreted base-Quaternary (Buckley 2012). The revised
base-Quaternary surface reaches a depth of 1248 ms TWT or approximately 1120 m
(assuming average velocity of 1800 m/s) showing an elongate basin shape that follows the
underlying structure of the Central Graben. The difference between the revised
base-Quaternary and the traditional base-Quaternary reaches a maximum of over 600
ms TWT or approximately 540 m in the south-west with over 300 ms TWT or
approximately 270 m at the Josephine well (56°36.11’N, 2°27.09’E) in the centre of the
basin.
Mapping this new base-Quaternary allows for the interpretation of the paleo-envionrment
during the earliest Quaternary. Seismic attribute analysis indicates a deep water basin with
sediment deposition from multiple deltas and redistribution by deep water currents. This has
strong implications for both the Quaternary climate archive and petroleum systems in the
North Sea.
Key Words: base-Quaternary; chronostratigraphy: seismic interpretation;
paleoenvironments
References
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From: Huuse, M., Redfern, J., Le Heron, D.P., Dixon, R.J., Moscariello, A., Craig, J. (eds)
‘Glaciogenic reservoirs and Hydrocarbon Systems’ Geological Society, London, Special
Publications, 368
Cameron, T.D.J., Stoker, M.S., Long, D., (1987) ‘The history of Quaternary
sedimentation in the UK sector of the North Sea Basin’ Journal of the Geological Society,
144, 43-58
Gatliff, R.W, Richards, P.C, Smith, K, Graham, C.C, McCormac, M, Smith, N.J.P, Long,
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Sejrup, H.P., Aareseth, I., Haflidason, H., 1991 ‘The Quaternary succession in the
northern North Sea’ Marine Geology 101 103-111 |
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