Abstract

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°; declination, D = 39.3°; α95 = 4.8°; N = 72 sites). Combined with local and regional geobarometric, metamorphic, and structural observations, the discordant paleomagnetic direction indicates east-side-up tilt by 16° about a tilt axis with azimuth = 8°. 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.

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