A revised biostratigraphic and well-log sequence-stratigraphic framework for the Scotian Margin, offshore eastern Canada 1This article is one of a series of papers published in this CJES Special Issue on the theme of Mesozoic–Cenozoic geology of the Scotian Basin. 2Earth Sciences Sector Contribution 20120137.

Abstract

In this study, we build on a foundation of previous biostratigraphic studies for the Scotian Basin, offshore eastern Canada, by conducting new quantitative multidisciplinary biostratigraphic studies of the Mesozoic sections in eight wells: Bonnet P-23, Chebucto K-90, Cohasset L-97, Glenelg J-48, Glooscap C-63, Mohican I-100, South Desbarres O-76, and South Griffin J-13. These wells were chosen to provide good spatial coverage, stratigraphic penetration, and correlation with the seismic grid. We have also evaluated pre-existing biostratigraphic data and undertaken the well-log sequence-stratigraphic interpretation of Upper Triassic to Cenozoic sediments in 16 additional wells using a consistent multidisciplinary event scheme derived from the new wells. Key to the dating of some horizons has been integration of the palynology and micropaleontology (disciplines mostly used previously on the Scotian Margin) with new nannofossil data. Simultaneously we have closely integrated the biostratigraphic results with lithofacies, well-log, and seismic interpretations. Using this integrated approach, we have identified nine regionally mappable sequence-stratigraphic events (unconformities and maximum flooding surfaces, or MFSs): the Intra-Oligocene Unconformity; the Ypresian Unconformity; the Turonian/Cenomanian Unconformity; the Late Albian Unconformity; the Aptian/Barremian Unconformity; the Intra-Hauterivian MFS; the Near-Base Cretaceous Unconformity; the Tithonian MFS; and the Top-Callovian MFS. Additional events of local extent were also recognized in some wells. Our study has led to significant revision of some previous lithostratigraphic picks. The Early Jurassic on the Scotian Margin remains poorly resolved and may be represented by an unconformity on much of the basin periphery.