Sea-floor spreading in the Gulf of Alaska

The data presented show that the magnetic lineations found off the west coast of the United States extend into the Gulf of Alaska. The magnetic pattern in the Gulf of Alaska is subparallel to the eastern limb of the Great Magnetic Bight of the northeast Pacific and is offset by one or more east-west fracture zones. The sequence of anomalies is continuous with those of the Great Magnetic Bight. The magnetic lineations are identified as a part of the lineation pattern recognized in the world's oceans. An offset migratory ridge system is proposed to explain the unique form of the lineations and the tectonic pattern of the north-east Pacific region in terms of ocean-floor spreading. Two episodes of spreading are suggested.