Abstract
The Canadian Cordillera is largely a mosaic of terranes that are allochthonous relative to the
autochthonous North American craton. Palaeobiogeographic data on pectinoid bivalves from various
cratonal areas and from two western Canadian terranes, Wrangellia and Stikinia, are used to estimate the
amounts of latitudinal displacement and rotation of these terranes that took place during and after
Early Jurassic times. Distributional patterns of various species of the distinctive, very common bivalve
Weyla, and a comparison of the positions of biogeographic boundaries between high-palaeolatitude,
mixed and low-palaeolatitude faunas on the terranes and on the craton indicate that Wrangellia was displaced
northward relative to the craton by at least several hundred and possibly more than 1000 km since
Sinemurian and Pliensbachian times. For Stikinia such estimates are even higher and exceed 1000 km.
Biogeographic patterns also suggest that Wrangellia experienced at best minor rotation since Sinemurian
times, while rotation from a more or less east–west alignment to its present northwest–southeast position
seems possible for Stikinia prior to the Pliensbachian. Palaeomagnetic interpretations, suggesting that
during Sinemurian and Pliensbachian times Wrangellia and Stikinia were in much the same latitudinal
position relative to the craton as they are now, are in sharp contrast to the results from faunal data. The
presence of warm oceanic surface currents, oceanographic effects of elongated barriers, climatic change
and differential latitudinal displacements due to rotation appear to be insufficient explanations for the
discrepancy between the interpretation of palaeomagnetic and faunal evidence.
Publisher
Cambridge University Press (CUP)
Cited by
23 articles.
订阅此论文施引文献
订阅此论文施引文献,注册后可以免费订阅5篇论文的施引文献,订阅后可以查看论文全部施引文献