Interpretation of seismic reflection data have led to a new model of the development of the Queen Charlotte Basin. New multi‐channel data collected in 1988 and an extensive network of unpublished older single‐ and multi‐channel profiles from industry image a complex network of sub‐basins. Structural styles vary along the axis of the basin from broadly spaced mainly N‐trending sub‐basins in Queen Charlotte Sound, to closely spaced NW‐trending sub‐basins in Hecate Strait, to an E‐W en echelon belt of sub‐basins in Dixon Entrance. Transtensional tectonics dominated in the Miocene and transpression dominated in the Pliocene except in Queen Charlotte Sound. The data we present prove that the origin of the basin is extensional and its most recent deformation is compressive. Evidence for the strike‐slip origin of tectonism includes along‐axis variations in structures, simultaneous extension and compression in adjacent sub‐basins, lack of correlations across faults, and mixed normal and reverse faults within structures. We infer that the Pacific‐North America plate boundary has been west of the Queen Charlotte Islands since the Miocene when relative plate motions have been dominantly strike‐slip. The formation and development of the Queen Charlotte Basin is the result of distributed shear; by which a small percentage of the plate motion has been taken up in a network of faults across the continental margin. As this region of crust deforms it interacts with neighbouring rigid crust resulting in extension dominating in the south of the basin and compression in the north. Continental crust adjacent to some transform plate boundaries can be sheared over a wide region; the network of basins in southwestern California is a good analogue for the Queen Charlotte Basin.

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The Cambrian-Permian successions in eastern Canada belong to three tectonostratigraphic domains, 1) the autochthonous St. Lawrence Platform, underlain by Cambrian to Devonian (?) rocks which extends from southern Quebec to western Newfoundland, 2) the Appalachians formed by Cambrian to Devonian rocks lying south and east of the St. Lawrence Platform and extending to the Atlantic Ocean, and 3) autochthonous Carboniferous to Permian rocks located offshore in the Gulf of St. Lawrence and in the onshore surrounding areas. Each succession contains unique source rock and reservoir units and specific trap types. Even though all of the basins contain producing or discovered hydrocarbon fields, there has been no recent evaluation of their ultimate oil and gas resource potential. A total of 15 conventional petroleum plays and 3 unconventional gas plays have been recognized in Paleozoic strata. Two conventional plays are recognized in Quaternary sediments. Of the 15 conventional Paleozoic plays, 6 have sufficient exploration and/or production data or good analogues to formulate a full quantitative assessment. Of these 6 plays, 4 are assessed for oil and gas potential, 1 for oil potential, and 1 for gas potential. Given the fact that a large number of conventional and all of the unconventional plays cannot be quantitatively assessed, the total resource presented herein is a minimum potential as evidence for hydrocarbon charge is compelling in most of the qualitatively assessed plays. The assessed plays of the eastern Canada Paleozoic basins have a cumulative median (P50%) in-place potential of 1170*109 m3 (41 Tcf) of natural gas and 403*106 m3 (2.5 BBO) of oil. The Carboniferous Maritimes Basin accounts for about 95% (1109*109 m3 or 39 Tcf) and 60% (235*106 m3 or 1.5 BBO) of the total gas and oil resource potential, respectively. The assessment results provide important new insights into the energy resource endowment of Paleozoic basins in eastern Canada. In particular, the assessment results indicate Carboniferous basins have a large gas resource potential, much higher than previously estimated. Moreover, the preliminary estimates from the industry (not quantitatively evaluated in this report) of the shale gas potential in the Ordovician succession alone, is assumed to be over 40 Tcf. Our sincere thanks to Jim Dixon who reviewed the initial draft and made very useful comments and suggestions for improvement.

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