Crustal Structure and Heat-Flow in the UK Rockall Basin, Derived from Backstripping and Gravity-Inversion Analysis

Seismic data provided by the UK OGA has been used to constrain a model of crustal structure and heat-flow history for the UK Rockall Basin. Top-basement/base-sediment has been interpreted around the full extent of the seismic dataset. This has produced a model for the thickness of the sediment fill which is thicker than previous published estimates.

The new sediment-thickness model has been incorporated into both a 3D-backstripping study and a 3D-gravity-inversion study. The results show crustal-basement thickness reduced to ~6km, thinning-factor ~0.8, in the south-central area of UK Rockall, while it spans the range ~6–10km further north. The results are compatible with previous seismic refraction work in both the UK and Irish sectors of the Rockall Basin. We believe that the extension which created the basin was non-magmatic and that the axial region is underlain by highly-thinned continental crust. The results from the gravity inversion have been used to make predictions about top-basement heat-flow history.

A regional gravity-inversion model, using the new sediment-thickness data spliced into regional public-domain information, shows that structural and stretching continuity can be mapped at the crustal scale along the full length of the UK/Irish Rockall Basin, contrary to conclusions from some previous studies.