The Jan Mayen Ridge: present status

Abstract

At present, there is no direct evidence of rocks predating the late Paleocene opening of the Norwegian- Greenland Sea on the Jan Mayen Ridge. A review of the available geophysical data, DSDP drilling results and plate tectonic reconstructions convincingly indicates a continental nature of the northern part of the ridge. On the other hand, there is still considerable uncertainty about the southern part of the ridge and its possible continuation towards Iceland. Two reflectors, A and 0, have been mapped regionally. A appears to reflect an unconformity of middle Oligocene age. Most investigators have indicated that 0 forms a late Paleocene rift unconformity associated with the opening of the Norwegian-Greenland Sea. By analogy with the North Sea and the continental margin off Norway we propose that it should be investigated whether this reflector might be older, relating to an earlier Mesozoic regime of tension.