The Blueflower Formation can be found outcropping in the Wernecke Mountains in Canada, and is a part of the wider Rackla Group. It is overlain by the Risky Formation,[1] whilst it is unconformably underlain by the dolostone Gametrail Formation.[4] The formation is also unique in preserving both deep-water and shallow-water environments. The shallow-water sections are primarily composed of siliciclastic rocks, with sandy-carbonates throughout, and is also fossiliferous in nature, meanwhile the deep-water sections are split into three members.[1]
The deep-water sections of this formation are composed of three members, two of which are informally named, which are as follows in stratigraphic order (lowest to highest):
Disk Member: This member is dominated by black shales, which is inter-bedded with siltstone, sandstone, and authigenic carbonate lenses and nodules. This member is also fossiliferous in nature, containing a number of discoidal forms such as Aspidella, which give the member its informal name.[4]
Upper Member: This member is predominately composed of sandstones, containing coarse-grained trough- and tabular-cross-bedded rocks, all of which is inter-bedded with shales.[4]
The base of the Blueflower Formation has been dated using Re–Os Dating, whilst the upper layers have been dated based on the fossil material. Using samples from the base of the formation, the recovered dates were 567.3±3Ma and 566.9±3.5Ma, placing the lower layers within the Avalon assemblage. Meanwhile, various fossils collected from rocks higher up in the formation are noted to be akin to formations placed within the White Sea and Nama assemblages, with the tentative proarticulateWindermeria correlating these layers to the White Sea assemblage.[2]
Unlike most other Ediacaran formations, the Blueflower Formation is unique in that is preserves shallow and deep-marine environments, and as it correlates with other Avalonian formations such as those in Newfoundland and Labrador, it allowed scientists to figure out whether the Ediacaran Biota started out in deep-marine environments before making their way into shallower waters.[1] The forms that can be found across the formation are the familiar Petalonamae such as Charniodiscus, including juvenile petalonamids from the Lower Member, and from the Upper Member tubular forms such as Annulatubus, and the enigmatic Windermeria.[1][2]
A recent paper also describes White Sea aged fossils within the lower sections of the formation, with the fossiliferous rocks being notably enriched in Carbon-13, an enrichment which has only been found in rocks dating to 567.3million years ago and 566.9million years ago, placing them within the Avalon assemblage and pushing their appearance some 7 million years before the White Sea assemblage begins, and includes organisms such as the olgunidFunisia and the proarticulate Dickinsonia. It is also the first example of White Sea assemblage organisms not only being found in a deep-water environment,[2] but also the first example of several organisms being found within Laurentia.[5]
12345678910111213Boag, 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.
1234567891011121314151617181920Evans, Scott D.; Sperling, Erik A.; Lau, Kimberly V.; Strauss, Justin V. (22 May 2026). "Discovery of White Sea assemblage fossils from Laurentia". Science Advances. 12 (21). doi:10.1126/sciadv.aed9916.
↑Aitken, J D (1989). "Uppermost Proterozoic formations in central Mackenzie Mountains, Northwest Territories". Geological Survey of Canada. doi:10.4095/126611.
1234Tarhan, Lidya G.; Hood, Ashleigh v. S.; Droser, Mary L. (March 2025). "Elevated Marine Dissolved Silica Levels Explain a Wide Range of Ediacaran–Cambrian Ediacara‐Style Fossil Deposits". Geobiology. 23 (2). doi:10.1111/gbi.70017.
↑Sperling, Erik A.; Carbone, Calla; Strauss, Justin V.; Johnston, David T.; Narbonne, Guy M.; Macdonald, Francis A. (March 2016). "Oxygen, facies, and secular controls on the appearance of Cryogenian and Ediacaran body and trace fossils in the Mackenzie Mountains of northwestern Canada". Geological Society of America Bulletin. 128 (3–4): 558–575. doi:10.1130/B31329.1.
123456789Hofmann, H. J.; Fritz, W. H.; Narbonne, G. M. (15 December 1983). "Ediacaran (Precambrian) Fossils from the Wernecke Mountains, Northwestern Canada". Science. 221 (4609): 455–457. doi:10.1126/science.221.4609.455.
12Narbonne, Guy M. (May 1994). "New Ediacaran fossils from the Mackenzie Mountains, northwestern Canada". Journal of Paleontology. 68 (3): 411–416. doi:10.1017/S0022336000025816.
12345678Carbone, Calla A.; Narbonne, Guy M.; Macdonald, Francis A.; Boag2024, Thomas H. (March 2015). "New Ediacaran fossils from the uppermost Blueflower Formation, northwest Canada: disentangling biostratigraphy and paleoecology". Journal of Paleontology. 89 (2): 281–291. doi:10.1017/jpa.2014.25.{{cite journal}}: CS1 maint: numeric names: authors list (link)
12Pyle, Leanne J; Narbonne, Guy M; James, Noel P; Dalrymple, Robert W; Kaufman, Alan J (June 2004). "Integrated Ediacaran chronostratigraphy, Wernecke Mountains, northwestern Canada". Precambrian Research. 132 (1–2): 1–27. doi:10.1016/j.precamres.2004.01.004.
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