Paleomagnetism of the Paleocene Ghost Rocks Formation, Prince William Terrane, Alaska

Abstract

The mean paleomagnetic inclination of Paleocene volcanics from two regions on Kodiak Island in the Ghost Rocks Formation suggests that the Prince William terrane originated at mid latitudes, about 25° south of its ‘expected’ Alaskan latitude in Paleocene time. The remanent magnetization of these rocks passes both the fold and reversal tests and is well constrained in age. The mean declinations of the two regions, however, differ by approximately 120°, suggesting they have rotated with respect to each other, perhaps during emplacement. We suggest that, despite the lack of evidence for a major Tertiary suture zone between the Prince William terrane and central Alaska, the Prince William and perhaps adjacent terranes may have lain substantially south of their present position in the Early Tertiary.