The sub-basaltic structure revealed by potential field methods on the Møre margin

Category Geophysic
Group GSI.IR
Location International Geological Congress,oslo 2008
Author Reynisson, Reynir Fjalar; Ebbing, Jِrg; Skilbrei, Jan Reidar
Holding Date 04 October 2008

The Møre volcanic margin is part of the mid-Norwegian margin and consists of a central area of NE-SW trending deep Cretaceous basin. The basin is flanked to the west by the Møre Marginal High that is characterized by thick, Early Eocene basalt flows overlying an unknown substrate. Numerous previous experiments have demonstrated that standard seismic acquisition and processing techniques are not capable of characterizing the volcanics or imaging beneath it.
A regional 3D crustal model of the Møre Margin was constructed based on the gravity and magnetic fields. The modelling process was constrained by seismic interpretations, well studies and published physical properties. The model managed to produce basalt thickness and sub-basalt basement structure maps.
A gravity gradient map showing the rate of change in the gravity signal across the main crustal lineaments on the Møre margin gives a good representation of the main regional structures on the margin. The gradient map also shows a good correlation to sub-basaltic structures predicted by the 3D model. Both the model and the gradient map indicate a sub-basaltic basement low on the Møre Marginal High extending from the SW to about 100 km to the NE. Comparison of the results to seismic data indicates the viability of the methods to predict the large scale sub-basaltic structure.
The results demonstrate that potential field methods are not a trivial aid in the sub-basaltic imaging problem. Integration with other geophysical tools like electromagnetics will further enhance the image of the sub-basaltic structures.