Paleomagnetism of the Upper Cretaceous strata of Mount Tatlow: evidence for 3000 km of northward displacement of the eastern Coast Belt, British Columbia

This study contributes the first paleomagnetic data from dated Cretaceous units of the Coast Belt (51.3°N, 123.8°W) in which paleohorizontal bedding surfaces can be identified with certainty. 38 sites were sampled through a 1.5-km stratigraphic interval of Cenomanian Silverquick sedimentary strata and Cenomanian to Campanian Powell Creek volcanics in the Tatlow syncline in the Tyaughton-Methow Basin. The results indicate that these rocks have been displaced northward by 3000 ± 500 km relative to cratonic North America since mid-Cretaceous time. This displacement is almost 3 times greater than that estimated from mid-Cretaceous volcanics in the now-adjacent Intermontane Belt. Evidently the two belts were not amalgamated until latest Cretaceous or Early Tertiary time. -from Authors