Paleomagnetism and geochronology of St. Matthew Island, Bering Sea

摘要: Oriented samples from a series of flow units, pyroclastics, tuffs, tuff breccias, and some intrusive rocks St. Matthew Island were studied paleomagnetically in an attempt to constrain possible paleolatitudes the Bering Sea shelf. The volcanic sequences have apparently stable magnetic directions contain reversed–normal–reversed–normal polarity succession.The Late Cretaceous paleolatitude deduced paleomagnetic data was 67°N, island has rotated clockwise sense by nominal 10°. This implies that analyzed formed about 12 °south their present location with respect cratonic North America. These argue against tectonic models for shelf region require large-scale Tertiary latitude changes.New K–Ar age dates combined previously reported ages give best estimate units 78.7 ± 0.4 Ma. reversed–normal–reversed changes are thought represent part ...