Paleomagnetism of the Upper Cretaceous Nanaimo Group, southwestern Canadian Cordillera

摘要: The Baja B.C. model has the Insular Superterrane and related entities of Canadian Cordillera subject to >3000 km northward displacement with respect cratonic North America from ~90 ~50 Ma. Upper Cretaceous Nanaimo Group (on about Vancouver Island, British Columbia) is a prime target test paleomagnetically because its locality age. We have widely sampled basin (67 sites seven islands spread over 150 km, Santonian Maastrichtian age). Most samples low unblocking temperatures (<450°C) coercivities (~10 mT) strong present-field contamination, forcing us reject three quarters collection. Beds are insufficiently tilted provide conclusive fold test, we see evidence relative vertical axis rotations. However, inclination-only analysis indicates pretilting remanence preserved for many samples. Both polarities observed, reversals correlate well paleontological data, proving that primary observed. mea...