--> Abstract: A Regional Overview of Salt Tectonic Sub-Provinces Beneath the Scotian Slope and Laurentian Fan, Offshore Eastern Canada, by J. W. Shimeld; #90039 (2005)

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A Regional Overview of Salt Tectonic Sub-Provinces Beneath the Scotian Slope and Laurentian Fan, Offshore Eastern Canada

 J. W. Shimeld
Geological Survey of Canada (Atlantic), Dartmouth, NS

Within the Scotian Basin, offshore of eastern Canada, Late Triassic to Early Jurassic evaporites of the Argo Formation are penetrated by 27 wells drilled along the continental shelf. As recognized early in the exploration history of the basin, deformation of these evaporites is linked to a significant number of the structures that occur beneath the continental shelf. Beneath the continental slope, various workers identified a 100 to 150 km wide belt known as the Slope Diapiric Province. The spectacular array of diapiric structures in this province were presumed to be related to deformation of the Argo Formation, but poor seismic imaging and sparse well control hampered efforts to understand tectonic relationships between the shallow and deep water portions of the basin.

Modern 2-D seismic data, with an average line spacing of 8 by 8 km, permit the definition of five tectonostratigraphic subprovinces beneath the Scotian Slope and Laurentian Fan. Primary salt basins exist beneath the two westernmost subprovinces where there is relatively simple passive diapirism above the source layer. Beneath the central Scotian Slope extensive allochthonous salt canopies occur beyond the depositional limit of the salt, creating a variety of thin-skinned extensional structures. There is a notable lack of diapiric structures beneath the eastern Scotian Slope due to the comparatively early development of a large-scale roho system seaward of the primary salt basin. Finally, in the easternmost subprovince, beneath Laurentian Fan, asymmetric structures manifest significant extension during the Cretaceous followed by contraction until at least the Neogene.

AAPG Search and Discovery Article #90039©2005 AAPG Calgary, Alberta, June 16-19, 2005