Aeromagnetic results and the presence of an extinct rift zone in western Iceland

Aeromagnetic surveys over western Iceland including Breidafjördur and Faxaflói bays reveal linear features which mostly have a northeasterly trend. However, this trend changes to a northerly direction as the lineations cross the Northwestern peninsula. Over the southern part of the area, the anomaly pattern may be fitted to a simple propagating-rift model. This model is consistent with results from geological mapping in western Iceland in the 1960s and 1970s which yielded evidence for an extinct (> 7 Ma old) rift zone west of the currently active rift zones. The magnetic data provide constraints on the process of rift zone movement and on the age of the bedrock offshore.