The mid-Proterozoic Little Dal macrobiota, Mackenzie Mountains, north-west Canada
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The Little Dal macrobiota is now known to comprise the previously reported carbonaceous megafossils Chuaria circularis, Tawuia dalensis, Moranial antiqua, and Beltina danai, as well as the following additional taxa: Longfengshania stipitata, Grypania spiralis, Daltaenia mackenziensis n.g. and sp., Tyrasotaenia sp., and Tyrasotaenia? sp. The dubiofossil 'Bergaueria?' reported earlier is probably nonbiogenic.Of special interest are three-dimensionally preserved specimens of Chauria, Tawuia, and Tyrasotaenia?, found associated with 'molar-tooth' structure. A carbonized test separates the pure, equigranular, microcrystalline calcite infilling of the fossil interior from an argillaceous carbonate matrix. This infilling is optically and chemically indistinguishable from that comprising the 'molar-tooth' structure. These relationships indicate comparable processes and timing for both fossilization of the organisms and filling of syneresis cracks during compaction and consolidation of the sediment.
Palaeontology - Volume 28 Part 2 Pages 331-354Palaeontology - Volume 28 Part 2 Pages 331-354
Citations
HOFMANN, H. J. 1985. The mid-Proterozoic Little Dal macrobiota, Mackenzie Mountains, north-west Canada. Palaeontology, 28, 2, 331–354.