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TitleThe type section of the Canol Formation (Devonian black shale) at Powell Creek: Critical assessment and correlation in the northern Cordillera, NWT, Canada
 
AuthorKabanov, P BORCID logo; Gouwy, S AORCID logo
SourceBulletin of Canadian Petroleum Geology vol. 68, no. 4, 2020 p. 123-140, https://doi.org/10.35767/gscpgbull.68.4.123
Image
Year2020
Alt SeriesNatural Resources Canada, Contribution Series 20210199
PublisherCanadian Society of Petroleum Geologists
Documentserial
Lang.English
Mediapaper; digital; on-line
File formatpdf; html
ProvinceNorthwest Territories; Yukon
NTS96C; 96D; 96E; 96F; 96K; 96L; 96M; 96N; 106
AreaPowell Creek; Mackenzie Mountains; Mackenzie River; Norman Wells
Lat/Long WENS-136.0000 -124.0000 68.0000 64.0000
Subjectsstratigraphy; paleontology; geochemistry; geophysics; Science and Technology; Nature and Environment; bedrock geology; lithology; sedimentary rocks; black shales; carbonates; limestones; systematic stratigraphy; type sections; stratigraphic correlations; lithostratigraphy; biostratigraphy; micropaleontology; microfossils; conodonts; tectonic setting; paleogeography; trace element geochemistry; geophysical logging; gamma ray logging; Canadian Cordillera; Mackenzie Plain; Canol Formation; Dodo Canyon Member; Vermillion Creek Member; Imperial Formation; Ramparts Formation; Carcajou Member; Phanerozoic; Paleozoic; Devonian
Illustrationstables; photographs; geoscientific sketch maps; cross-sections; plots; correlation sections; gamma ray logs; biostratigraphic charts
ProgramEnergy Geoscience Program Coordination
Released2021 12 15
AbstractThe Canol Formation is only 24.5 m thick at its historic type section at Powell Creek, northern Mackenzie Mountains, whereas in the off-bank sections of the Mackenzie Plain subsurface, where it is considered a high-quality shale hydrocarbon prospect, it thickens to 60-120 m. This paper reviews available lithological and conodont biostratigraphic information from the type section, discusses choices of contacts and subdivisions, and explores the limits of regional correlation using gamma spectrometry proxies. We position the base of the Canol Formation at the top of the lower resistant unit of the 'allochthonous limestone beds', the thick off-reef debris package present in this outcrop but absent in other well-known Canol sections. The base of the formation can be of a latest Givetian age as suggested by the norrisi zone conodont fauna from the 'allochthonous limestone'. The top of the Canol Formation is placed at the base of a distinct, 2.1 m thick horizon with concretionary carbonate beds within the thick shale transition between the Canol and the Imperial formations. Limestone nodules from this horizon produced a conodont fauna that can occur in the jamieae to Upper rhenana zones (Frasnian zones 11-12) thereby suggesting a middle to earliest Late Frasnian age for the Canol top. The cross-section tying several outcrop and well sections across the regional facies zonation reveals that the Dodo Canyon Member, a unit erected in thick off-bank Canol sections, is traceable at Powell Creek. In this correlation, the Vermillion Creek Member, which is the lower portion of the Canol Formation in thick off-bank sections, finds its counterpart in the allochthonous limestone beds sensu MacKenzie (1970). This cross-section is the first correlation of the Canol stratotype at member level available in published sources. Thinness of the Canol Formation at Powell Creek, as well as its location in the carbonate bank toe-of-slope setting, are factors impairing its reference value and calling for more representative sections to act as reference sections and constitute a composite-stratotype for the Canol Formation.
Summary(Plain Language Summary, not published)
Sedimentary rocks require type sections (sections are transects measured perpendicular to strata) which hold the historic definitions and names of formal rock packages (called lithostratigraphic units) as a prerequisite to their handling by natural resource exploration and science. The Canol Formation is one of such formal rock units, and its historical type section is an outcrop at Powell Creek in the Canyon Ranges of the northern Mackenzie Mountains. The Canol Formation is important both economically (major shale oil and gas potential) and in the fundamental science where it provides indispensable information about the greenhouse ocean-atmosphere system of the remote Past (383-375 million years ago). This paper evaluates published data on the Powell Creek outcrop making emphasis on rock descriptions, instrumental measurements, and the age-defining fossils called conodonts. Although limited ability to trace rock strata from the type Canol section to other outcrops and boreholes is demonstrated, the Canol Formation is too thin at Powell Creek (only 23.4 m of typical Canol rocks) , and its lower part is too unusual for the majority of Canol sections. Therefore, another principal reference section should be selected and adequately characterized in order to max out the use of the lithostratigraphic unit called the Canol Formation.
GEOSCAN ID328685

 
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