Great Canadian Lagerstätten 2. Macroand Microfossils of the Mount Cap Formation (Early and Middle Cambrian, Northwest Territories)

The Early–Middle Cambrian Mount Cap Formation, NWT, hosts a diverse range of exceptionally preserved fos sils. Like the celebrated Burgess Shale of British Columbia, the Mount Cap contains carbonaceous compression fossils of animals that lacked mineral ized hard parts, as well as the fully articulat...

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Bibliographic Details
Main Authors: Harvey, Thomas H. P., Butterfield, Nicholas J.
Format: Article in Journal/Newspaper
Language:English
Published: Geological Association of Canada 2011
Subjects:
Online Access:https://journals.lib.unb.ca/index.php/GC/article/view/18965
Description
Summary:The Early–Middle Cambrian Mount Cap Formation, NWT, hosts a diverse range of exceptionally preserved fos sils. Like the celebrated Burgess Shale of British Columbia, the Mount Cap contains carbonaceous compression fossils of animals that lacked mineral ized hard parts, as well as the fully articulated skeletons of shelly taxa. Its unique importance, however, lies in exceptional carbonaceous preservation at a microscopic scale. Acid-extracted microfossils from the ‘Little Bear biota’ of the Mackenzie Mountains reveal important details of problematic groups including chancelloriids and hyolithids, and provide direct evidence of Cambrian diets in the form of fae cal strings. A complementary microfos sil assemblage from the subsurface of the Colville Hills region contains an extraordinary diversity of exquisitely preserved arthropod cuticle, and con stitutes the oldest known record of complex crown-group crustaceans. We discuss the wider significance of the Mount Cap fossils, and describe some new forms that point to the potential for future discoveries. La Formation de Mount Cap dans les T.N.-O. qui va du début de Cambrien jusqu’au Cambrien moyen renferme une gamme diverse de fossiles excep tionnellement bien préservés. Comme dans le cas des schistes de Burgess de Colombie-Britannique, la Formation de Mount Cap renferme des fossiles de compression carbonés d’animaux exempts de parties dures minéralisées, de même que de squelettes pleinement articulés de taxons coquillers. Cepen dant, son importance unique tient à sa préservation carbonée exceptionnelle à l’échelle microscopique. Les microfos siles obtenus par extraction à l’acide sur le « biote de Little Bear » des monts Mackenzie montrent d’impor tants détails sur des groupes controver sés incluant les chancelloriidés et les hyolithidés, ainsi que des indices directs de la diète cambrienne sous la forme de trainées fécales. Un assemblage microfossile complémentaire du sous sol de la région de Colville contient une extraordinaire diversité de cuticules ...