Abstract

Pennsylvanian to Early Jurassic sediments underlie part of Prince Patrick Island but are absent on Banks Island. From Early Jurassic through Early Tertiary time the Banks-Prince Patrick area underwent fairly continuous sedimentation. A slower subsidence rate than in the Mackenzie Delta and Sverdrup Basin depocentres gave rise to correspondingly smaller sediment thickness.

A late Early Jurassic marine transgression covered most of Prince Patrick Island and Eglinton Graben and probably filled much of Banks Basin. Thick sands and shales resulted (Wilkie Point and Mould Bay Formations). In the Aptian, uplift and block faulting caused a regression and created local troughs in which fluvial sediments accumulated (Isachsen Formation). Sediment was derived from the craton and from local fault-bounded uplifts (?including Storkerson Uplift). Vertical sequences of sedimentary structures demonstrate stream rejuvenation and shifting channel patterns, both thought to have been caused by continued syndepositional fault movement.

Succeeding argillaceous and silty beds (Christopher Formation) reflect an Albian marine transgression. A Late Albian shoreline sand facies developed in Eglinton and northern Banks Island (Hassel Formation) and an Early Cenomanian regression followed. Marine sedimentation may have continued in Big River Basin, while mild erosion ensued elsewhere in the report area. Renewed, eastward transgression commenced in the Turonian but did not reach eastern Banks until Late Campanian time. Prince Patrick Island remained uplifted until the Late Tertiary.

Silty shale accumulated in the Banks area during the Late Cretaceous (Kanguk Formation). A Campanian shoreface sand facies developed on the flanks of Storkerson and Cape Crozier Uplifts, while extrusive volcanism may have occurred in the vicinity of western Banks Island.

Fault rejuvenation and differential uplift from Maastrichtian through Eocene time caused deltaic wedges to prograde from Storkerson Uplift and the craton into Banks and Big River Basins (Eureka Sound Formation). Fourier analysis of gamma ray logs shows that coarsening upward clastic cycles therein thicken with present basin depth, indicating a Tertiary origin for the present structural configurations.

Uplift and erosion during the Oligocene was followed by subsidence of present offshore areas and commencement of a major deltaic phase which continued to the present. Beaufort Formation is part of this assemblage, which thickens seaward to several thousands of feet.