HR: 1340h
AN: OS23C-1330    [Abstracts]
TI: Tertiary Sequences And Quaternary Glacial Sediments Of The Southern North Sea, Europe
AU: * Hermann, K
EM: kudrass@bgr.de
AF: BGR, Stilleweg 2, Hannover, D 30655 Germany
AU: Lutz, R
EM: l.reinhardt@bgr.de
AF: BGR, Stilleweg 2, Hannover, D 30655 Germany
AU: Christoph, G
EM: gaedicke@bgr.de
AF: BGR, Stilleweg 2, Hannover, D 30655 Germany
AU: Ruediger, L
EM: r.lutz@bgr.de
AF: BGR, Stilleweg 2, Hannover, D 30655 Germany
AU: Michael, W
EM: michael.wiedicke@bgr.de
AF: BGR, Stilleweg 2, Hannover, D 30655 Germany
AB: The southern North Sea with a focus on the German exclusive economic zone was surveyed by multichannel seismic (airgun) and shallow seismic (boomer and sparker). The seismic lines, with their special focus on the shallow subsurface, complement data sets of varying quality of scientific (e.g., 2D seismic and wells of the EC Southern North Sea Project) and commercial origin (2D/3D seismic and wells of hydrocarbon exploration). The different data sets were integrated in a digital interpretation system. Interpretation was supported by numerous shallow (6 m) cores targeted at key sites. On a large scale, key reflectors are mapped below and above the prominent Middle Miocene unconformity leading to a better understanding of the prograding Eridanos delta throughout the Tertiary. Also a first subdivision of the Quaternary sequence has been achieved. The most prominent structures in the shallow subsurface are widespread ramified subglacial valleys of likely Elsterian age (~400 kyr BP), which can be up to 400 m deep and which generally have a complex infill. Another prominent feature is a shallow depression of the sea floor starting NW of Heligoland and spanning far north into Danish waters. This elongated depression ("Elbe-Urstromtal" Figge, 1980) is interpreted to be eroded by periglacial rivers running southward and westward of the ice sheet. On a regional scale, some studied 3D-seismic volumes allow the identification of more subtle structures in time slices like widespread iceberg keel scours and ice sheet scours. Also remnants of the morphology of the glacial landscapes seem to be preserved represented by contrasting seismic facies of patchy, rough moraines and more uniform planes. The planes are incised by up to 4 intersecting systems of gullies, channels, and valleys that are of supposed fluvial and subglacial origin. Recurrent seismic anomalies with exceptional high amplitudes may indicate shallow gas in subsurface sediments.
DE: 9335 Europe
DE: 4219 Continental shelf processes
DE: 4243 Marginal and semienclosed seas
DE: 3022 Marine sediments--processes and transport
DE: 3025 Marine seismics (0935)
SC: Ocean Sciences [OS]
MN: 2004 AGU Fall Meeting