Frontiers and Opportunities in Antarctic Geosciences * Certosa di Pontignano * 29-31 July 2004
High-Resolution 2d Backstripping of a Plio- Pleistocene Prograding Wedge on
the Mid-Norwegian Continental Margin (EC Stratagem)
S. CERAMICOLA 1, L. DE SANTIS 1, J.S LABERG 2, B.O. HJELSTUEN 3
1 - Istituto Nazionale di Oceanografia e Geofisica Sperimentale, Trieste, Italy
2 – University of Tromsø, Norway
3 - University of Bergen, Norway
*Corresponding author (sceramicola@ogs.trieste.it)
Flexural backstripping allows an analysis of basin subsidence, but also provides information on the differential
responses to sediment loading (by compaction and flexure) in the form of palinspatic reconstructions of palaeo-seafloor
geometries along a profile.
This study applies a 2D flexural backstripping technique to two depth-converted seismic profiles (NPD JJ’ and DD’)
across the Norwegian margin to investigate the response to the rapid deposition of a 1.5 km thick prograding wedge
(Naust Formation, <4 Ma). Flexural backstripping was applied to four Plio-Pleistocene Naust Fm sub-units (one glacial
and three pre-glacial) to produce successive palaeo-depth restorations across the continental margin at the estimated
time of deposition of the units. The results were constrained using palaeo-bathymetries estimated from well data and
regional markers (e.g. buried iceberg scour depths) that indicate rapid late Cenozoic subsidence of the Norwegian
margin, coeval with onshore uplift.
The results show important changes in palaeo-seafloor geometries in response to rapid loading by the Naust Formation.
Sediment progradation shifted the shelf break seaward by up to a few hundred kilometres (profile NPD DD’). At the
same time, sediment loading induced differential flexural deflections, such that previously flat-lying surfaces now have
a relief of up to 1 km (profile NPD DD’). These deflections inverted pre-existing structural configurations in places, but
in others enhanced their actual convexity (profile NPD JJ’), e.g. of Tertiary inversion domes (i.e. Nagflar Dome, Nick
High and Uitgard High).