Palaeobathymetry and Tectonic Evolution of Lower Jurassic Source Rocks of the Conjugate Nova Scotia-Moroccan Margins (part of the PAGEO research program)

This project will address key questions related to the formation processes, structure and subsidence history of the Nova Scotia rifted margin, which are relevant to constrain the Upper Triassic to Jurassic palaeogeography and petroleum systems offshore Nova Scotia.

The project will focus on investigating the sedimentary, tectonic and magmatic processes, the resulting structures and segmentation, and the consequences for the palaeobathymetry and depositional environments of Lower Jurassic basins within the Nova Scotia margin and its Western Moroccan conjugate. To account for the spatial and temporal variations related to rift migration and breakup propagation during the Early to Middle Jurassic, the project will also include investigations of the evolution of adjacent regions including the southern Grand Banks, Gulf of Cadiz and onshore remnants of the same system cropping out onshore Morocco (Rif belt and Atlas).

The project will address three objectives: (1) the high resolution palaeobathymetric evolution of the Nova Scotia rifted margin during the Jurassic; (2) the crustal architecture, palaeobathymetry and segmentation of the conjugate Nova Scotia – Western Moroccan rifted margins; and (3) the integration of Nova Scotia in the opening framework of the Western Tethys and southern North Atlantic.

The researchers will apply a workflow of integrated quantitative geophysical and geodynamic analyses to structural and stratigraphic observations. The project team will use a 2D/3D flexural-backstripping technique, which includes reverse modelling of the post-breakup lithosphere thermal subsidence to predict the palaeobathymetry and palaeostructure at breakup. They will also perform 2D/3D subsidence analyses to determine the lithosphere stretching and thinning as well as thickness variations of the remaining continental crust. Observations and interpretations derived from the analysis of reflection seismic and well data will be supplemented by geological field data from the on-land counterpart preserved in Northern Morocco in the Rif belt.

As part of this workflow, a gravity inversion component will:

  • Map Moho depth and crustal thickness using gravity inversion for the Nova Scotia and Moroccan margins; 
  • Use joint inversion of time-seismic and gravity anomaly data to test and validate Moho interpretations of regional 2D reflection and recently acquired high-resolution 3D seismic surveys for the Nova Scotia margin;
  • Produce conjugate margin crustal cross-sections for the Nova Scotia and Moroccan margins showing Moho depth, basement thickness and lateral variation of basement density;
  • Combine the results of gravity and joint inversion from this workflow with residual depth analysis and lithosphere thinning results to complete an integrated quantitative analysis and determine rifted margin domains and the continent-ocean boundaries of the Nova Scotia and Moroccan margins; and
  • Develop a crustal architecture model for offshore northern Morocco for the purpose of comparison with offshore Nova Scotia and the shared syn-rift evolution of these conjugate margins

Principal Investigators: Geoffroy Mohn, Julie Turgend, CY Cergy Paris Université, France; Nick Kusznir, Badley Geoscience Ltd., Spilsby, UK

December 2020 – July 2022