A paleomagnetic study of certain Mesozoic formations in northern Mexico

Rocks of Late Cretaceous, Early Jurassic and Late Triassic age, collected in northern Mexico yield the following pole positions: 169.3°E57.9°N (Cretaceous), 70.7°E76.0°N (?Jurassic) and 119.2°E76.4°N (?Late Triassic). The Triassic and Cretaceous poles are not significantly different from those class-A poles (Hicken et al., 1972) of the North American craton. It is therefore suggested that the North American craton may be traced south as far as 23°N and inferentially a further four degrees (to the Mexican volcanic belt).The results from the La Boca Formation are interpreted as indicating a much greater age (Late Precambrian-Early (Paleozoic) than is currently assigned to that formation.