Models of Cretaceous plate motion have commonly assumed that North America remained stationary throughout the entire Cretaceous period, and rapid spurts of continental drift occurred in the earliest and latest Cretaceous (e.g., Irving et al., 1993). According to the generalized Cretaceous compilation (Irving et al., 1993), the sites drilled during Leg 171B, which are presently at a latitude of 30°N, have a predicted mid-Cretaceous (Hauterivian to Santonian) paleolatitude of 30°N, a rapid Late Cretaceous northward drift to a Campanian-Maastrichtian position at 40°N, followed by a return southward to reach their present position in the late Tertiary.
However, the array of paleolatitudes from Aptian through Eocene from the five sites indicates that a remarkably stable paleolatitude of about 25°N was maintained during this time span (Table T6; Fig. F8). All sites and all sediment facies yield quite similar values. There is no evidence of any significant paleolatitude shifts during this interval. Indeed, the apparent motion during the late Tertiary merely consisted of a minor northward drift (<5°) rather than the southward motion from current models of North American polar wander.
This array of Leg 171B results, which are the most detailed continuous paleolatitude records of any location on the North American plate, suggests that the current Cretaceous through early Tertiary polar wander path for North America may contain artifacts of poor age constraints on magnetically suitable sediments on the North American craton and inadequate statistical processing of relevant paleomagnetic results. The "stable Cretaceous pole" of North America has been significantly mispositioned southward by nearly 10° latitude.
A reanalysis of the North American paleomagnetic database (C. MacNiocaill, L. Bardot, and J. Ogg, unpubl. data) is consistent with our paleolatitude path from the Blake Nose margin transect.