Clarke Campbell

Now that hydrocarbon exploration is moving into the deepwater Scotian Slope, specifically the areas basinward of the Sable and Abenaki sub-basins, a better understanding of the evolution and controlling factors of the complex allochthonous salt nappe systems of the deepwater Scotian Slope is needed. A lack of exploration wells and seismic imaging problems associated with the complex salt bodies hinder structural interpretation in these areas. Through scaled physical modelling of salt tectonics and sedimentation processes in rift basins with different basement morphologies, expected in the Scotian Basin new structural and mechanical concepts have been developed to support seismic interpretation in this area. These concepts include: 1) Downbuilding of sediments as the dominant mechanism of initial salt movement in the landward part of the rift basins with thick salt (2 km). 2) The salt thickness due to the basement floor morphology, rather than the geometry of the basinward rift shoulder, is the controlling factor for how efficiently landward downbuilding inflates the basinward autochthon salt, and later evacuates salt into the allochthon canopy and nappe systems. 3) The timing and rate of the allochthonous nappe advancement into the deepwater basin is dependant on the efficiency of early salt evacuation and mid-stage progradation of sediments over the inflated autochthon basinward salt complex. These concepts derived from the physical experiments can be applied for the interpretation of complex salt structures observed in seismic lines along the deepwater Scotian Margin and can help to correlate and interpret the observed salt structures and their depositional environment in terms of initial rift basin geometry and related salt thickness. Both parameters are difficult to observe directly in the geophysical data but are essential for the interpretation of the deepwater slope setting.

Keywords: Salt tectonics, allochthonous salt nappe systems, Scotian Margin, analogue modelling.
Pages: 94
Supervisor: Juergen Adam