ABSTRACT

The Queen Charlotte Basin is a 50,000 km² upper Paleogene-Neogene basin underlying the Queen Charlotte Islands, Hectate Strait and Queen Charlotte Sound region of the British Columbia continental margin. The basin formed as a result of Eocene to Pliocene extension along and adjacent to a transform segment of the Pacific - North America plate boundary. Oblique subduction along the plate boundary since Pliocene time has resulted in uplift and (transpressive?) folding of portions of the northern half of the basin. Well-log correlations, outcrop studies, and new offshore seismic profiles indicate that the basin is a composite of half-grabens and sub-basins separated and underlain by complexly structured pre-Tertiary rocks. Most of the offshore sub-basins contain siliciclastic sediments in excess of 3,000 m thick, and strata as thick as 6,000 m occur locally. The older (pre-Pliocene) part of the basin-fill locally contains volcanics, commonly interbedded with clastics. Potential hydrocarbon reservoirs within the basin include alluvial fan, fan-delta and tidal-shelf sandstones. Potential hydrocarbon source rocks include Upper Triassic-Lower Jurassic shales and limestones locally preserved below the basin, and Tertiary shales within the deeper portions of the basin-fill. Possible hydrocarbon traps include compressive folds, rollover anticlines, basement fault blocks, and a variety of combined structural-stratigraphic traps. The Queen Charlotte Basin is considered to be one of the most prospective areas for hydrocarbon resources along the northeast Pacific margin.

End_of_Record - Last_Page 161-------