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New Ediacaran fossils from the uppermost Blueflower Formation, northwest Canada: disentangling biostratigraphy and paleoecology

Published online by Cambridge University Press:  04 June 2015

Calla A. Carbone ,
Guy M. Narbonne ,
Francis A. Macdonald  and
Thomas H. Boag
Calla A. Carbone
Affiliation:
Department of Geological Sciences and Geological Engineering, Queen’s University, Kingston, ON, K7L 3N6, Canada, 〈c.carbone@queensu.ca〉; 〈narbonne@queensu.ca〉; 〈thomas.boag@mail.utoronto.ca〉
Guy M. Narbonne
Affiliation:
Department of Geological Sciences and Geological Engineering, Queen’s University, Kingston, ON, K7L 3N6, Canada, 〈c.carbone@queensu.ca〉; 〈narbonne@queensu.ca〉; 〈thomas.boag@mail.utoronto.ca〉
Francis A. Macdonald
Affiliation:
Department of Earth and Planetary Sciences, Harvard University, 20 Oxford St., Cambridge, MA 02138, USA, 〈fmacdon@fas.harvard.edu〉
Thomas H. Boag
Affiliation:
Department of Geological Sciences and Geological Engineering, Queen’s University, Kingston, ON, K7L 3N6, Canada, 〈c.carbone@queensu.ca〉; 〈narbonne@queensu.ca〉; 〈thomas.boag@mail.utoronto.ca〉
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Abstract

New Ediacaran fossil finds at Sekwi Brook occur in lower shoreface to offshore transition beds at the top of the Blueflower Formation, which are the most shallow-water facies and the youngest strata in which Ediacara-type fossils have been described from the Mackenzie Mountains of NW Canada. Newly discovered Ediacaran body fossils include two new tubular genera: Sekwitubulus annulatus new genus new species was a mm-diameter rigid annulated tube that was rooted to the sea bottom by a holdfast; Annulatubus flexuosus n. gen. n. sp. was a cm-diameter, flexible annulated tube. In conjunction with previously described large attachment discs representing the form-genus Aspidella and a single specimen of the dickinsonid Windermeria, these fossils define an assemblage that differs markedly from the rangeomorph-dominated deeper-water and older assemblages lower in the same section at Sekwi Brook. In contrast, trace fossils show little change upwards through the Blueflower Formation, at least in part reflecting their origin by microbial grazers on mats that formed during low-energy periods in both deep- and shallow-water environments. This implies that the stratigraphic succession of Ediacaran fossils in NW Canada and probably globally represents both evolutionary changes with age and the paleoecology of specific depositional settings.

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Articles
Information
Journal of Paleontology , Volume 89 , Issue 2 , March 2015 , pp. 281 - 291
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Copyright © 2015, The Paleontological Society 

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