| Title | Neoproterozoic-Cambrian stratigraphy of the Mackenzie Mountains, northwestern Canada, part I: Ediacaran measured sections and updated lithostratigraphy, NE Sekwi Mountain map area (NTS 105-P) |
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| Licence | Please note the adoption of the Open Government Licence - Canada
supersedes any previous licences. |
| Author | MacNaughton, R B |
| Source | Geological Survey of Canada, Open File 7315, 2020, 22 pages, https://doi.org/10.4095/327237  Open Access |
| Image |  |
| Year | 2020 |
| Alt Series | Northwest Territories Geological Survey Contribution 0145 |
| Publisher | Natural Resources Canada |
| Document | open file |
| Lang. | English |
| Media | on-line; digital |
| Related | NRCan photo(s) in this
publication |
| Related | This publication is related to the following
publications |
| File format | pdf |
| Province | Northwest Territories |
| NTS | 105P/15; 105P/16 |
| Area | Mackenzie Mountains; Sekwi Mountain; Godlin River |
| Lat/Long WENS | -129.0000 -128.0000 64.0000 63.7500 |
| Subjects | regional geology; stratigraphy; Science and Technology; Nature and Environment; Lower Cambrian; systematic stratigraphy; stratigraphic analyses; stratigraphic nomenclature; stratigraphic correlations;
lithostratigraphy; bedrock geology; lithology; sedimentary rocks; dolostones; sandstones; arenites; siltstones; shales; carbonates; sedimentary structures; Canadian Cordillera; Neoproterozoic; Ediacaran; Ediacaran-Cambrian boundary; Backbone Ranges
Formation; Gametrail Formation; Sheepbed Formation; Nadaleen Formation; Risky Formation; Phanerozoic; Paleozoic; Cambrian; Precambrian; Proterozoic |
| Illustrations | location maps; geoscientific sketch maps; stratigraphic charts; lithologic logs; photographs; tables |
| Program | GEM2: Geo-mapping for Energy and Minerals Mackenzie Corridor |
| Released | 2020 09 30 |
| Abstract | This report updates Ediacaran stratigraphic assignments in the northeastern part of NTS map area 105-P (Sekwi Mountain map area). A previous report (MacNaughton et al., 2008) included graphic logs for
three measured sections in this region. The sections were thought to encompass the uppermost part of the Sheepbed Formation, a platform facies of the Gametrail Formation, the lower and middle members of the Backbone Ranges Formation, and the basal
part of the upper member of the Backbone Ranges Formation. The sections were considered to span much of the Ediacaran and possibly the basal Cambrian. Based on more recent bedrock mapping, as well as revisions to regional stratigraphic correlations,
the measured sections from the earlier report are reassessed. An interval previously treated as a sandy, shallow-marine upper part of the otherwise shale-dominated Sheepbed Formation is reassigned to the lower member of the Backbone Ranges Formation.
The contact between the two units corresponds to an upward change from dark grey to brown or rusty weathering colours. In the area where the sections were measured, the 'Sheepbed carbonate' is not present at the Sheepbed-Backbone Ranges contact, nor
is the shale-rich Nadaleen Formation (a.k.a. 'June beds'), although these units are commonly present at this level in other parts of the Mackenzie Mountains. A thick package of shallow-marine, grey sandy dolostone and dolomitic sandstone, previously
assigned to the Gametrail Formation is also placed in the lower member of the Backbone Ranges Formation, based on comparison with other sections regionally. In light of recent studies, measured strata in the basal part of the upper member of the
Backbone Ranges Formation probably are Ediacaran rather than Cambrian. Previously unpublished descriptive notes are provided for the three measured sections. |
| Summary | (Plain Language Summary, not published)
This report has two purposes. First, the report places in the public domain previously unpublished descriptive notes that were the basis for an earlier
GSC report, published in 2008. These provide important basic data for several Ediacaran-aged geological units in the Mackenzie Mountains, NWT. Second, the report updates some conclusions from the 2008 article to reflect more recent studies in the
Mackenzie Mountains by university researchers and by the Geological Survey of Canada. |
| GEOSCAN ID | 327237 |
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