Plate tectonic significance of repeated tectonic trends in eastern Canada

Abstract

THE existence of generally parallel, major tectonic structures of different ages has been long recognised. In Eurasia, for instance, the Alpine Orogenic Belt is parallelled by the Hercynian–Variscan Orogenic Belt, and in southern New Brunswick there is a general parallelism between the Alleghenian (Variscan) and Acadian fold belts¹. In Newfoundland² the Acadian Fold Belt runs generally parallel to the older, late Cambrian–earliest Ordovician (Grampian) Fold Belt in the west and a pre-middle Ordovician fold belt in the east. Further, the Appalachian-Caledonian Belt as a whole in north-eastern Canada runs parallel to the older (1,000 Myr BP) Grenvillian Orogenic Belt for at least 1,000 miles. These are clearly indications of continental accretion (Fig. 1).