Abstract

In order to test the various estimates of the accretion age of some of the southern Alaska terranes, a paleomagnetic investigation of the MacColl Ridge Formation (latest Cretaceous age) in the Wrangell Mountains (Wrangellia) was undertaken. The data pass the fold test and reversal test, thus affirming the primary nature of the magnetic remanence. The mean paleomagnetic direction corresponds to a paleolatitude of 32°±9°, which is far south of the predicted paleolatitude, assuming a North American paleogeography. Therefore, these results apparently rule out a pre-Cenozoic accretion age of Wrangellia and its associated terranes composing the Southern Alaska superterrane. The data also imply about 130° counterclockwise rotation, which is the opposite sense of rotation usually observed in western North America.

You do not currently have access to this article.