Abstract

Sedimentary rocks and sediments, representing seven systems from Late Devonian to Pleistocene are found offshore from Nova Scotia and Newfoundland. They reach a thickness of more than 12 km and overlie a metasedimentary and igneous basement complex from late Precambrian to Devonian in age. In the early Mesozoic, the portion of Pangaea occupied by the modern Atlantic continental margin of Canada was emergent and undergoing erosion in a hot and arid climate. During the Triassic, precursor stresses to continental breakup resulted in the development of linear troughs along the southeastern edge of the Appalachian Orogen which were initially filled with red continental elastics. Progressive subsidence permitted connection with the Tethys, resulting in evaporitic conditions which persisted into the Early Jurassic. In middle Early Jurassic a major transgression was initiated, which, by Late Jurassic time had spread the sea to within fifty miles of the south coasts of Nova Scotia and Newfoundland and resulted in the deposition of thick sequences of clastics and carbonates. South of Nova Scotia, sea floor spreading began in the early Middle Jurassic initiating the development of the modern Atlantic Ocean Basin. This area was connected, via a narrow seaway across the northern Grand Banks, to a developing basin east of Newfoundland.

In the Early Cretaceous, a second stage of plate decoupling occurred with the Iberian Peninsula moving away from the eastern Grand Banks. This resulted in uplift, mild deformation and some erosion of Jurassic strata across the Grand Banks, while Lower Cretaceous paralic sequences were deposited in the adjacent depositional areas. The Late Cretaceous was a time of regional transgression with resultant overlap of Jurassic sediments. Shallowing of the sea began in the Late Tertiary during which time a wedge of regressive clastic sediments was deposited. In latest Tertiary there was rapid progradation of clastic sequences across the shelf areas in response to eustatic lowering of sea level.