Wynniatt Formation
| Wynniatt Formation | |
|---|---|
| Stratigraphic range: Tonian [1] | |
| Type | Geological Formation |
| Sub-units | Member 1, 2, 3 and 4 |
| Underlies | Kilian Formation [2] |
| Overlies | Boot Inlet Formation [2] |
| Thickness | 500 - 800 m (1,640 - 2,624 ft) |
| Lithology | |
| Primary | Dolomite |
| Other | Mudstone, Siltstone, Quartz arenite, Sandstone, Limestone, Gabbro |
| Location | |
| Region | Nunavut |
| Country | Canada |
The Wynniatt Formation is a geologic formation in Nunavut. It preserves enigmatic fossils dating back to the Middle to Late Tonian period, around 850 Ma - 760 Ma.[3]
Paleoenviroments
[edit]Due to the large thickness of the Wynniatt Formation, it is broken up into 4 Members, simply named "Member" 1 - 4, and from the rocks contained within these 4 members, a rough idea of what the paleoenviroments may have looked across the formation are as follows:[2]
- Member 1 : Periodically exposed inter-tidal mudflat.
- Member 2 : Shallow sub-tidal to inter-tidal with layers of microbial mat, and is also the fossil bearing member.[3]
- Member 3 : Extensive shelf-marginal reef complex, which itself is overlain by deposits of lagoons and a back-reef agal flat.
- Member 4 : Cycles of shallow sub-tidal to inter-tidal.
Paleobiota
[edit]After Butterfield, 2005.[3]
Color key
|
Notes Uncertain or tentative taxa are in small text; |
| Genus | Species | Notes | Images |
|---|---|---|---|
| Cheilofilum |
|
Enigmatic 1.2mm long filamentous organism. | |
| Chuaria |
|
Enigmatic fossil, possibly synonymous with Tawuia. | |
| Clavitrichoides |
|
Enigmatic filamentous organism, most material from this formation are possibly less well preserved Cheilofilum. | |
| Osculosphaera |
|
Enigmatic filamentous organism. | |
| Plicatosphaeridium |
|
Enigmatic filamentous organism. | |
| Tappania |
|
Acanthomorph acritarch. | .jpg) |
| Tawuia |
|
Enigmatic fossil, possibly an alga. |  |
See also
[edit]
References
[edit]- ^ van Acken, David; Thomson, Danielle; Rainbird, Robert H.; Creaser, Robert A. (October 2013). "Constraining the depositional history of the Neoproterozoic Shaler Supergroup, Amundsen Basin, NW Canada: Rhenium-osmium dating of black shales from the Wynniatt and Boot Inlet Formations". Precambrian Research. 236: 124–131. doi:10.1016/j.precamres.2013.07.012.
- ^ a b c Rainbird, R. H.; Jefferson, C. W.; Young, G. M. (April 1996). "The early Neoproterozoic sedimentary Succession B of northwestern Laurentia: Correlations and paleogeographic significance". Geological Society of America Bulletin. 108 (4): 454–470. doi:10.1130/0016-7606(1996)108<0454:TENSSB>2.3.CO;2.
- ^ a b c Butterfield, Nicholas J. (June 2005). "Reconstructing a complex early Neoproterozoic eukaryote, Wynniatt Formation, arctic Canada". Lethaia. 38 (2): 155–169. doi:10.1080/00241160510013231.
- Various Contributors to the Paleobiology Database. "Fossilworks: Gateway to the Paleobiology Database". Retrieved 17 December 2021.
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