Two active transform faults are identified on land in Iceland. This observation leads to a new interpretation of the tectonics of Iceland that is generally consistent with the available geologic, geomorphic, and geophysical data. This new interpretation provides a framework that can be used to relate detailed geologic and geophysical studies in Iceland to worldwide processes at the crests of mid-ocean ridges.
Nearly one-half of Iceland seems to have formed during a period of very slow spreading between about 9 and 20 m.y. B.P. The center of spreading within Iceland apparently shifted from western to eastern Iceland around 7 or 8 m.y. B.P. Iceland, the largest landmass on the mid-ocean ridge system, may have resulted from a change in the stress pattern on a broad fracture zone, allowing large volumes of lava to be erupted while there was little regional spreading.