Neoproterozoic fossils from the Franklin Mountains, northwestern Canada: stratigraphic and palaeobiological implications
Samuelsson, J.; Butterfield, N.J. (2001). Neoproterozoic fossils from the Franklin Mountains, northwestern Canada: stratigraphic and palaeobiological implications. Precambr. Res. 107(3-4): 235-251. dx.doi.org/10.1016/S0301-9268(00)00142-X
In: Precambrian research. ELSEVIER SCIENCE BV: Amsterdam; London; New York; Oxford; Tokyo. ISSN 0301-9268; e-ISSN 1872-7433, more
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| Keywords |
Proterozoic
Acritarcha [WoRMS]
Marine/Coastal |
| Author keywords |
proterozoic; neoproterozoic; microfossils; acritarchs; stratigraphy;cordillera |
| Authors | | Top |
- Samuelsson, J.
- Butterfield, N.J.
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| Abstract |
Shales from the Lone Land Formation of the Cap Mountain inlier, southern Franklin Mountains, and 'pre-Palaeozoic' horizons of a nearby drillhole (Shell Blackwater Lake G-52) have yielded two distinct fossil assemblages. The presence of Trachyhystrichosphaera aimika (in G-52) and Chuaria circularis tin the Lone Land) identifies both sections as Neoproterozoic; previous lithostratigraphic correlations with Mesoproterozoic strata on the Coppermine Homocline are not supported. Marked differences in thermal alteration of the fossils suggest that the two successions are not related despite their present geographic proximity; whereas the G-52 fossils are medium orange in colour, those in the Lone Land are brown. We argue that the Cap Mountain succession is allochthonous and originated probably to the west of its present position. By contrast, the G-52 assemblage shows marked similarity to a fossil in the Wynniatt Formation (Shaler Supergroup) of Victoria Island. Compound and/or coiled filaments are abundant in the G-52 assemblage and appear to be associated generally with exceptional fossil biotas in the Neoproterozoic; insofar as these are likely to document particular environmental conditions, they may help to identify the locus of early eukaryotic diversification. The tendency of some prokaryotes to aggregate and form compound structures also has implications for interpreting various problematic macrofossils, including putative seaweeds from the Palaeoproterozoic Negaunee Iron Formation. We erect a new genus and species, Gemmuloides doncookii n. gen., n. sp. from the Lone Land Formation. |
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