Geology and geodynamics of Iceland

Iceland is located where the asthenosperic flow under the the NE Atlantic plate boundary interacts and mixes with a deep-seated mantle plume. The buoyancy of the Iceland plume leads to dynamic uplift of the Iceland plateau, and high volcanic productivity over the plume produces a thick crust. (Fig.1). The Greenland-Færöy ridge represents the Icland plume track through the history of the NE Atlantic. The current plume stem has been imaged seismically down to about 400 km depth (Tryggvason et al. 1983; Wolfe et al. 1997, 2002), throughout the transition zone (Shen et al. 1998; Shen et al. 2002) and more tentatively down to the core-mantle boundary (Helmberger et al. 1998; Bijwaard and Spakman 1999). During the last 60 Ma Greenland, Eurasia and the NE Atlantic plate boundary have migrated northwestwards at a rate of 1-3 cm/a relative to the surface expression of the Iceland plume (Fig. 1; Lawver and Muller, 1994). Currently, the plume channel reaches the lithosphere under the Vatnajökull glacier, about 200 km southeast of the plate boundary defined by the Reykjanes and Kolbeinsey Ridges (e.g. Wolfe et al. 1997). During the last 20 Ma the Icelandic rift zones have migrated stepwise eastwards to keep their positions near the surface expression of the plume, leading to a complicated and changing pattern of rift zones and transform fault zones.