Early Tertiary paleomagnetic evidence and the displacement of southern Alaska

Abstract

Paleomagnetic data from early Paleocene lavas, a few kilometers north of Lake Clark just inboard of the Peninsular terrane, indicate modest post-early Tertiary latitudinal displacement and about 55/sup 0/ of counterclockwise rotation of this region with respect to North America. A nearby middle Eocene sequence of lava flows, however, gives no indication of displacement or rotation. South of Lake Clark, the paleomagnetism of five Paleogene (30 to 40 Ma) volcanic sequences that are a part of the Peninsular terrane proper shows no northward translation and no rotation. A major part of the northward movement documented by other studies in the Gulf of Alaska region may be accounted for by cumulatively significant intraterrane displacements. 32 references, 3 figures, 1 table.