Abstract

Crude sand model experiments to simulate a mid-Paleozoic oblique collision between a laterally stepped North American (Grenville) continent and a straight-edged African continent show the development of two sets of transcurrent faults; one parallel to the colliding margins, and one in the direction of approach. In nature, the transcurrent faults parallel to the ancient continental margin were reactivated with vertical motion during the Carboniferous which established the boundaries of the developing Fundy epieugeosyncline. The second system of faults is represented by the Cobequid-Chedabucto fault system. The outline of the mid-Paleozoic North American margin and the collision-initiated faults can be recognized by variations in the potential fields. The Cobequid-Chedabucto fault system is associated with the land fall of a major gravity and magnetic anomaly (the Collector Anomaly) which is associated with a shear zone in the mid-Paleozoic African continent. Granites may have been intruded along the western margin of the Meguma Platform when southern Nova Scotia moved westwards and collided with New Brunswick and Maine following shearing of the African block. North of the shear zone all trends are flexed into the Collector Anomaly, denoting major deformation of that block and the extension of Precambrian basement beneath much of the Grand Banks. The northeast Newfoundland Shelf is underlain by subsided continental crust, the inshore bounding fracture line being the locus for the development of a deep, linear sedimentary basin.