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TitleCarboniferous and Permian reefs of Sverdrup Basin, Canadian Arctic: an aid to Barents Sea exploration
AuthorBeauchamp, B
SourceArctic geology and petroleum potential; by Vorren, T O (ed.); Bergsager, E (ed.); Dahl-Stamnes, Ø A (ed.); Holter, E (ed.); Johansen, B (ed.); Lie, E (ed.); Lund, T B (ed.); Norwegian Petroleum Society (Npf), Special Publication vol. 2, 1993 p. 217-241,
Alt SeriesGeological Survey of Canada, Contribution Series 36991
Mediapaper; on-line; digital
File formatpdf
ProvinceNunavut; Northern offshore region
Subjectsmarine geology; fossil fuels; fossil reefs; reefs; Artinskian; depositional environment; deposition; algal reefs; algal mounds; basins; sedimentary basins; water temperature; dolomitization; diagenesis; petroleum exploration; Sverdrup Basin; small patch reefs; wide tabular banks; large reef-mounds; bryozoan reefs; Carboniferous; Permian
AbstractHundreds of Carboniferous and Permian reefs occur in the Sverdrup Basin, Canadian Arctic Archipelago. Reef occurrences span the Bashkirian to Artinskian time interval. There are three basic morphological types: small patch reefs, wide tabular banks, and large reef-mounds. Each type reflects the amount of space available for buildup growth in various depositional environments (inner to outer shelf, shelf-edge, slope). Biologically, Sverdrup reefs can be grouped into three broad categories: bryozoan reefs, algal reefs and mixed reefs. The three categories coexisted throughout most of the Bashkirian to Sakmarian interval, with bryozoan reefs occurring in deep water and algal reefs in shallow water; mixed reefs occupied an intermediate position. With time, the bryozoan reef belt expanded, as the algal and mixed reef belts were contracted into increasingly narrower belts against the basin margin. By Artinskian time, all niches from inner shelf to slope were occupied by bryozoan reefs. This trend parallels a major cooling trend in the Sverdrup Basin in late Paleozoic time and indicates that both temperature and water depth were the main controls on buildup types. Most Sverdrup reefs are tightly cemented by early and late diagenetic carbonate phases, but meteoric diagenesis and dolomitization led, in some cases, to a considerable porosity enhancement. The best reef prospects for oil and gas exploration are: subaerially exposed tabular banks; fault-controlled dolomitized reef-mounds; and evaporite-encased dolomitized reef-mounds.