Jan Mayen, related to ridge-transform-plume or ridge-transform interactions?

Jan Mayen, an active volcanic island in the North Atlantic (71ºN), is located at the Jan Mayen fracture zone that separates the ultra-slow spreading Kolbeinsey and Mohns ridges. The volcanic island has been interpreted to form above a mantle plume, to be related to the Icelandic plume, to result from leaky transform volcanism, or to have formed by southward propagation of the Mohns ridge into a microcontinent situated south of the Jan Mayen fracture zone. The location of the southernmost segment of the Mohns ridge has been poorly defined, and the relation between the ridge and volcanic island volcanisms has therefore been unclear. Dredge sampling and ROV survey followed multibeam mapping of the Jan Mayen region and the Mohns ridge during two cruises in the summer of 2001. These surveys demonstrated that the neovolcanic zone of the Mohns ridge intersects the Jan Mayen fracture zone about 60 km east of Jan Mayen. Mapping and dredge sampling demonstrated also that Jan Mayen does not extend north of the Jan Mayen fracture zone. The volcanic island does therefore not define the southernmost tip of the Mohns ridge, and is not related to propagation of this ridge across the fracture zone and into the margin of a micro-continent located south of the fracture zone. Bathymetry and lineament analyses suggest that the northern, and highly active part of the volcanic island may represent a very short spreading segment within the fracture zone. Submarine lava flows from the northern part of Jan Mayen, and the southern segments of the Mohns ridge were systematically dredge sampled. Elemental and isotopic compositions of these basalts will be reported and discussed in terms of Jan Mayen being related to ridge-transform-plume or just ridge-transform interactions, and the influence of the Iceland plume on the Arctic ridges.