Abstract

Basins are defined, for the purposes of this paper, as areas with stratigraphically continuous rock sequences. Thirty-four of these basins are catalogued for areas of the Atlantic borderlands, north of present latitude 50° N. Key references are listed for each, and brief summaries of sediment fill, environments and tectonic setting are given.

A brief general summary of the fill of the basins is based on the major distinction between coastal and inland fills. Fining-upward cycles in sandstone and siltstone sequences are particularly a feature of coastal fills, and lacustrine environments are particularly a feature of the inland fills.

Extensive high-angle faults of Devonian age are a feature of many of the basins. These trend parallel to fold trends in the pre-Devonian basement, and often provide evidence of horizontal (strike-slip) motion. It is suggested that these faults are a surface expression of major, deeper, faults that formed as a result of continent-continent collision. Granites may have been generated and emplaced along these deep faults. Only two or three of the Devonian basins appear to have formed as a direct result of the horizontal fault motion at the surface. More commonly, the basins appear to have formed from late vertical movements, along the earlier and deeper faults after their strike-slip initiation. These vertical movements could have been caused either by the granite emplacement or by other thermal disturbances. Basin formation by movement associated with the deep faults was typical of the basins internal to the orogenic belt and presumed to have been on the main collision zone. Other basins external to the main orogenic belt do not appear to reflect the same fault origin.