Structure, Tectonics, and Petroleum Systems Offshore Newfoundland

Abstract

Prior to rifting in the Cretaceous, the Grand Banks, offshore Newfoundland, were part of Pangaea and were situated at the intersection of what are now the North American, Iberian and Eurasian Plates. We present a revised structural and tectonic model for the three plaate system that includes: a) high-resolution structural mapping from multi-satellite gravity data; b) depth-to-basement, depth-to-Moho, crustal and sediment thickness maps calculated from 3D inversion of potential field data, and c) a new kinematic plate reconstruction for the North America-Iberia-Eurasia rift system, including the rifts that were aborted prior to the onset of seafloor spreading. We identified four major tectonic events and sedimentary megasequences that have influenced the Grand Banks and its neighbouring areas:

Late Triassic–Early Jurassic widespread rifting along the eastern margin of North America and the margin of Northwest Africa, which was associated with the initial break-up of Pangaea and the formation of the Central Atlantic Ocean.

An Early Cretaceous rifting event that focussed on the Newfoundland margin and the conjugate West Iberian margin and caused the separation of the Iberian and North American continents during the Aptian and Albian.

A Late Cretaceous near-perpendicular rifting event that reactivated the northern basins of the Grand Banks as it propagated northwestward from the Bay of Biscay into the Labrador Sea and Baffin Bay. This rifting event initiated the separation of Europe and Greenland from North America.

Early Cenozoic rifting and break-up returned to its original northeastward strike when Europe rifted from Greenland. At the end of the Eocene, the oceanic ridge in the Labrador Sea became extinct, returning Greenland to the North American Plate as Europe drifted eastwards from Greenland.

Analysis of crustal structure and deformation style reveals a degree of asymmetry between the Newfoundland and West Iberian margins; the presence of a wide region of exhumed mantle offshore western Iberia reduces petroleum potential. Although not directly conjugate, there may be value in using the basins offshore western Ireland and the UK as analogues to Newfoundland.Our model allows the study of the European and Canadian margins alongside each other, enabling direct comparisons to be made between basins that were both direct conjugates and those that were laterally continuous as rifts propagated.

AAPG Datapages/Search and Discovery Article #90323 ©2018 AAPG Annual Convention and Exhibition, Salt Lake City, Utah, May 20-23, 2018