Abstract
The post-rift history of the North Viking Graben has been backstripped in 3D, producing a sequence of palaeobathymetric maps that culminates at the Late Jurassic synrift stage. The backstripping takes into account the three main processes which drive post-rift basin development: thermal subsidence, flexural-isostatic loading and sediment compaction. Before backstripping was performed, the Norwegian Trench, a bathymetric feature within the present-day seabed, was smoothed in order to remove associated decompaction artefacts within the backstripping results. Palaeobathymetric restorations at the top and base of the Paleocene take into account regional transient dynamic uplift, probably related to the Iceland Plume. 350 m of uplift is incorporated at the Base Tertiary (65 Ma) and 300 m at the Top Balder Formation (54 Ma), followed by rapid collapse of this same uplift. At the top of the Lower Cretaceous (98.9 Ma), very localized fault-block topography, inherited from the Jurassic rift, is predicted to have remained emergent within the basin. At the Base Cretaceous (140 Ma), the fault-block topography is much more prominent and numerous isolated footwall islands are shown to have been present. At the Late Jurassic synrift stage (155 Ma), these islands are linked to form emergent island chains along the footwalls of all of the major faults. This is the Jurassic archipelago, the islands of which were the products of synrift footwall uplift. The predicted magnitude and distribution of footwall emergence calibrates well against available well data and published stratigraphic information, providing important constraints on the reliability of the results.
Highlights
At the top of the Lower Cretaceous (98.9 Ma), very localized fault-block topography, inherited from the Jurassic rift, is predicted to have remained emergent within the basin
The post-rift history of the North Viking Graben has been backstripped in 3D, producing a sequence of palaeobathymetric maps which culminates with a Late Jurassic synrift restoration at 155 Ma
The backstripping model has taken into account the three main processes which drive post-rift basin subsidence and development, notably: (i) thermal subsidence; (ii) flexural-isostatic loading; and (iii) sediment compaction
Summary
This paper, derived from what was initially a commercial study, aims to fill this gap by presenting a sequence of palaeobathymetric maps for the North Viking Graben, produced by application of the established technique of 3D flexural-backstripping and reverse thermalsubsidence modelling (Roberts et al 2009, 2013, 2018)
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