Petrology and geochemistry of a dredged clinopyroxenite-dolerite basal complex from the Jan Mayen volcanic province, Norwegian-Greenland Sea

Abstract Serpentinised plagioclase-olivine clinopyroxenite and dolerite fragments were dredged from the western Jan Mayen Fracture Zone, near its intersection with the Kolbeinsey Ridge. According to major and trace element analyses of the rocks and minerals (a) the clinopyroxenite represents cumulates which crystallised from a Jan Mayen-like alkaline magma at an intermediate basaltic stage in the uppermost mantle or lower crust, and (b) the dolerite fragments constitute an oceanic, within-plate tholeiitic series with alkaline affinities. These rocks have been subjected to serpentinization, low-medium grade metamorphism, metasomatism, brecciation and veining, part of which probably took place during fracture zone tectonism. By analogy with the geological development of the Canary Islands, they are considered to form part of a layered basal complex to the alkaline Jan Mayen volcanic province.