Abstract

There are two allochthonous salt canopies within the central Scotian margin, one on the shelf and another in deeper waters on the Scotian slope. The Sable Shelf Canopy trends southwest–northeast and covers an area approximately 650 km2. Salt thickness within this canopy is generally <1000 m. Reloading of the salt has welded out the margins of the canopy, significantly reducing its extent. Salt tectonics related to this canopy produced many of the exploration targets drilled on the shelf. The Sable Slope Canopy is 50 km basinward on the Scotian slope. This canopy is significantly larger, covering 12 700 km2, and the allochthonous salt is as thick as 3500 m. Although the two canopies are separated by a significant distance, a common detachment surface connects them in multiple locations. Extensional systems detach in the Sable Shelf Canopy, displace strata downdip, and expel salt into the Sable Slope Canopy. The outer shelf and slope region separating these two canopies is dominated by detachment systems. One term, the Sable Canopy Complex, was developed to describe both salt canopies and the zone of detachment that separates them. Interpretation of two-dimensional and three-dimensional seismic data throughout the Sable Canopy Complex has resulted in a detailed allochthonous salt map and all related components including welded systems, salt stocks, faults, sutures, and minibasins. Four distinct expulsion styles are observed to contribute volumes of salt to the canopies: salt-based detachments, counterregional systems, hybrids, and salt stocks. Potential explanations for the variations in expulsion style range from varying volumes of sediment input to paleogeographic positions on the margin to salt sheet length.

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