Sheepbed Formation
| Sheepbed Formation | |
|---|---|
| Stratigraphic range: Ediacaran | |
| Type | Formation |
| Unit of | Rackla Group[1] |
| Sub-units | Lower and Upper Member |
| Underlies | Nadaleen Formation[1] |
| Overlies | Cliff Creek Formation[1] |
| Thickness | 400 metres (1,300 ft) |
| Lithology | |
| Primary | Shale[1] |
| Other | Dolostone[1] |
| Location | |
| Region | Northwest Territories |
| Country | Canada |
The Sheepbed Formation is a geologic formation in Northwest Territories, which is dominated by shale despoits, and capped by a layer of dolostone.[1]
History
[edit]In 1989, a paper by Aitken was published describing the discovery of the fossil genus Kullingia in the then 'Upper-most Sheepbed Formation'.[2] Further discoveries were made a year later in 1990 by Narbonne & Aitken, ranging from Charniodiscus to Sekwia.[3]
Although in 2013 and 2014, studies found that this fossiliferous unit was in fact not a part of the Sheepbed Formation, due to the coarser nature of the shales, and is separated from the Sheepbed Formation by major regional sequence boundary, marked by large channel fills. As such, it is noted this strata, previously referred to as the "June Beds" and now formally known as the Nadaleen Formation,[1] is younger in age than the Sheepbed Formation. As such, there are currently no known fossils from within Sheepbed.[4][5]
See also
[edit]
References
[edit]- ^ a b c d e f g h Boag, Thomas H.; Busch, James F.; Gooley, Jared T.; Strauss, Justin V.; Sperling, Erik A. (May 2024). "Deep‐water first occurrences of Ediacara biota prior to the Shuram carbon isotope excursion in the Wernecke Mountains, Yukon, Canada". Geobiology. 22 (3). doi:10.1111/gbi.12597.
- ^ Aitken, J (1989). "Uppermost Proterozoic formations in central Mackenzie Mountains, Northwest Territories". Energy, Mines & Resources Canada, Geological Survey of Canada.
- ^ Narbonne, Guy M; Aitken, James D. "Ediacaran fossils from the Sekwi Brook area, Mackenzie Mountains, northwestern Canada" (PDF). Paleontology.
- ^ Macdonald, Francis A.; Strauss, Justin V.; Sperling, Erik A.; Halverson, Galen P.; Narbonne, Guy M.; Johnston, David T.; Kunzmann, Marcus; Schrag, Daniel P.; Higgins, John A. (December 2013). "The stratigraphic relationship between the Shuram carbon isotope excursion, the oxygenation of Neoproterozoic oceans, and the first appearance of the Ediacara biota and bilaterian trace fossils in northwestern Canada". Chemical Geology. 362: 250–272. doi:10.1016/j.chemgeo.2013.05.032.
- ^ Narbonne, Guy M.; Laflamme, Marc; Trusler, Peter W.; Dalrymple, Robert W.; Greentree, Carolyn (2014). "Deep-Water Ediacaran Fossils from Northwestern Canada: Taphonomy, Ecology, and Evolution". Journal of Paleontology. 88 (2): 207–223. ISSN 0022-3360.
- Various Contributors to the Paleobiology Database. "Fossilworks: Gateway to the Paleobiology Database". Retrieved 17 December 2021.