Basins and fold belts of Prince Patrick Island and adjacent area, Canadian Arctic Islands

Abstract

Prince Patrick and Eglinton islands have a polar desert climate and a landscape of coastal plains and dissected plateaux with limited vegetation cover. Use of a properly damped surveyor's compass is possible, however, magnetic declination changes markedly over short distances and large temporal variations are present. Bedrock of the report area is divisible into four major successions. These include: 1) 14 to 18 km of Proterozoic(?) and/or older bedrock above the Mohorovicic Discontinuity; 2) 10 to 14 km of thermally overmature but variably tectonized ("Franklinian") strata that range from Vendian(?) at the base through Upper Devonian at the top; 3) less than 1 km grading to more than 7 km of thermally mature and immature, relatively undeformed Carboniferous through Lower Cretaceous strata of the Sverdrup Basin, including up to 2 km of Middle Jurassic through Upper Cretaceous strata preserved in four peripheral basins and numerous small grabens; and 4) 70 m to more than 600 m of unconsolidated Pliocene sand, gravel, and peat, and related seismically defined Neogene strata of the Arctic Continental Terrace Wedge. The Franklinian succession is further subdivided into siliciclastic rocks of the Devonian clastic wedge (up to 6000 m thick), subsurface Lower Devonian and older strata of the Prince Patrick Platform, and correlative seismically defined deep-water strata of Canrobert Trough. A thrust-fold belt imaged seismically in the northeast is continuous with folds known at the surface on northwestern Melville Island, and folded Devonian strata are everywhere separated from Carboniferous and younger rocks by a profound angular unconformity. Other lower Paleozoic folds extend under southwestern Prince Patrick Island. A Carboniferous rift system located under the Sverdrup Basin margin has developed on the eroded roots of the Paleozoic fold belt. The rift formed in the Early Carboniferous (Serpukhovian), expanded to the southwest during the later Carboniferous, and was partly inverted during the Early Permian. Mid-Permian through early Middle Jurassic was a time of passive subsidence and progressive basin expansion toward the southwest. During Sverdrup Basin subsidence, four intracratonic basins, separated by Devonian "basement" highs, developed to the southwest between Middle Jurassic and Late Cretaceous time. An array of northerly trending horsts and grabens also developed during this time, part of a rift system that provides a geological record of the early development of the Arctic Ocean basin. Potential exists for far-travelled hydrocarbons within the Permo-Carboniferous and Jurassic-Cretaceous rift systems and in stratigraphic traps on the margins of the Mesozoic basins. Subbituminous coal seams to 1.5 m occur in Lower Cretaceous strata, and deposits of manganese carbonate are widespread in Campanian sandstone of Eglinton Island.

Chapter 35 Regional seismic interpretation of crustal framework, Canadian Arctic passive margin, Beaufort Sea, with comments on petroleum potential

“…35.10). The Palaeozoic stratigraphy of the western Arctic Islands, including the subsurface of Banks Island, is similarly correlative (Harrison & Brent 2005). This stratigraphy does not apply to the Beaufort Foldbelt segment that is founded upon the Arctic Alaska Terrane.…”

“…The Palaeozoic and Proterozoic sequences beneath the Mesozoic rift sediments are identified in wells drilled in the basin margin along the Tuk (vernacular abbreviation of Tuktoyaktuk) Peninsula and Banks Island and outcrops south of the coastal plain (Figs 35.3 & 35.4). Similarly, syn-rift sediments recognized onshore include Late Jurassicearliest Cretaceous rocks and predate the breakup unconformity dated as latest Valanginian-earliest Hauterivian, 134 Ma, on-land (Embry & Dixon 1990;Harrison & Brent 2005). On oceanic crust a similar breakup unconformity post-dating all seafloor spreading in the Canada Basin, as observed on profiles in this study, is constrained to be no younger than c. 117 Ma (mid-Aptian) because magnetic stripes in the Canada Basin could not have formed much after the onset of the M0 Aptian -Santonian Cretaceous normal polarity superchron (Gurevich et al 2006;Grantz et al 2007).…”

Analysis of large thermal maturity datasets: Examples from the Canadian Arctic Islands

“…This suggests that the lower Paleozoic samples are thermally matured at a higher temperature than would be expected from their burial compaction. Given the location of these wells in the western Arctic, in the area of Jurassic-Early Cretaceous rifting of the Canada Basin (Harrison and Brent, 2005), it seems likely that the elevated vitrinite reflectance was due to an increased thermal gradient during rifting rather than deep burial during the Ellesmerian Orogeny.…”

“…This compressive event is termed the Eurekan Orogeny (Thorsteinsson and Tozer, 1970;Harrison et al, 1999). Deformation generated long wavelength folds and reactivated salt diapers across the entire Sverdrup Basin (Harrison and Brent, 2005;Jober et al, 2007).…”

Eos, Transactions, American Geophysical Union Volume 90, Number 23, 9 June 2009

“…In the northern part of the Canada Basin (Figure 2b), many subbasement refl ections occur, including dipping events, similar in geometry to fan-shaped features that could represent extensional rift basins or seaward dipping refl ections associated with magmatism. Neither interpretation can be ruled out because of the known history of multiple rifting events in the area [Harrison and Brent, 2005] and because of the area's proximity to Alpha Ridge, part of the High Arctic large igneous province [Maher, 2001]. In the central Canada Basin (Figure 2c), the basement is more deeply buried, highly faulted, and of higher relief than elsewhere in the basin.…”