Neogene tilting of crustal panels near Wrangell, Alaska

A late Oligocene-Miocene igneous complex south and west of Wrangell, Alaska, contains mafic dikes that yield a discordant paleomagnetic direction (inclination, I = 70.4[degrees]; declination, D = 39.3[degrees]; [[alpha].sub.95] = 4.8[degrees]; N = 72 sites). Combined with local and regional geobarometric, metamorphic, and structural observations, the discordant paleomagnetic direction indicates east-side-up tilt by 16[degrees] about a tilt axis with azimuth = 8[degrees]. Neogene tilt of crustal blocks in the Insular superterrane accounts for much of the paleomagnetic discordance in Cretaceous plutons without the coastwise translation of >1000 km, as suggested by the Baja British Columbia hypothesis. Keywords: Coast orogen, southeast Alaska, paleomagnetism, Neogene crustal extension.