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TitleBiostratigraphy and paleoecology of the trilobite faunas from the Mount Clark and Mount Cap formations (early and middle Cambrian), eastern Mackenzie Mountains, northwestern Canada
 
AuthorHandkamer, N MORCID logo; Pratt, B RORCID logo; MacNaughton, R BORCID logo
SourceJournal of Paleontology vol. 96, S89, 2022, 47 pages, https://doi.org/10.1017/jpa.2022.13
LinksData - Données
Image
Year2022
Alt SeriesNatural Resources Canada, Contribution Series 20210288
Alt SeriesJournal of Paleontology Memoir 89
PublisherCambridge University Press
Documentserial
Lang.English
Mediapaper; digital; on-line
File formatpdf
ProvinceNorthwest Territories
NTS96D/05; 96D/06; 96D/07; 96D/10; 96D/11; 96D/12; 96D/13; 96D/14; 96D/15
AreaMackenzie Mountains; Mackenzie River; Keele River
Lat/Long WENS-128.0000 -126.5000 65.0000 64.2500
Subjectspaleontology; stratigraphy; environmental geology; sedimentology; Science and Technology; Nature and Environment; Middle Cambrian; Lower Cambrian; biostratigraphy; paleoecology; fossils; faunas; depositional environment; fossil zones; systematic paleontology; taxonomy; evolution; fossil descriptions; bedrock geology; lithology; structural features; anticlines; Mount Clark Formation; Mount Cap Formation; Trilobites; Mackenzie Arch; Laurentia; Stony Anticline; MacDougal Anticline; Foran Anticline; Mackenzie Plain Depocentre; Phanerozoic; Paleozoic; Cambrian
Illustrationslocation maps; geoscientific sketch maps; correlation charts; photographs; stratigraphic sections; plots; pie charts
ProgramGEM2: Geo-mapping for Energy and Minerals Mackenzie Corridor, Shield to Selwyn
ProgramGeoscience for New Energy Supply (GNES)
Released2022 06 24
AbstractLower and middle Cambrian strata of the eastern Mackenzie Mountains, Northwest Territories, Canada, were deposited in a semi-enclosed basin along the eastern flank of the Mackenzie Arch. The Mount Clark Formation is predominantly composed of nearshore sandstone and is overlain by deeper water siltstone, mudstone, and carbonates of the Mount Cap Formation. The contact between these formations is interpreted as a flooding surface. Trilobite biostratigraphy indicates the presence of the traditional upper Olenellus through Glossopleura zones (Cambrian Series 2, Stage 4-Miaolingian, Wuliuan) and suggests the flooding surface is diachronous, spanning the Dyeran-Delamaran boundary. Above the Olenellus Zone, the Amecephalus arrojosensis-Eokochaspis nodosa Zone, the new Aitkenaspis keelensis Zone, the new Albertelloides mischi Zone, and the Glossopleura walcotti Zone are recognized. Whereas the older zones are comparable to those in other areas of Laurentia, the trilobite faunas in the Albertelloides mischi and Glossopleura walcotti zones show a greater abundance of zacanthoidids and dolichometopids. They also have a lower diversity of ptychoparioids and oryctocephalids, and lack agnostoids, eodiscoids, dorypygids, and ogygopsidids. This suggests that zacanthoidids and dolichometopids were able to tolerate conditions that were unfavorable to the other groups, probably related to semi-restricted conditions in the basin. Four endemic species exhibit characteristics that are considered paedomorphic. This developmental process took place in three separate lineages, suggesting that heterochrony was also environmentally provoked.
New taxonomic names are authored by Handkamer and Pratt. New genera are Eobathyuriscus, Sahtuia, Mexicaspidella Aitkenaspis, Dodoella, and Mackenzieaspis. New species are Bolbolenellus dodoensis, Eobathyuriscus mackenziensis, E. macqueeni, Glossopleura youngi, Sahtuia carcajouensis, Aitkenaspis keelensis, Albertelloides eliasi, Dodoella kobayashii, Mackenzieaspis parallelispinosa, and M. divergens.
Summary(Plain Language Summary, not published)
This reports documents fossil trilobites (ancient, extinct arthropods) from two units of rock deposited in the Mackenzie Mountains, NWT, during the early and middle parts of the Cambrian Period (roughly 500-520 million years ago). The rock units are the Mount Clark and Mount Cap formations, which host oil and gas in the subsurface of northern mainland Canada. The trilobites are documented in detail, including the naming of several new genera and species. This detailed documentation means that the rocks can be correlated more accurately from place to place. This may help with more successful exploration for oil and gas, and will definitely contribute to more accurate models for the geological evolution of the regional-scale sedimentary basin within which these rocks were deposited.
GEOSCAN ID328943

 
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