Sirius Passet

Age

The fauna is inevitably compared to that of the Burgess Shale, although it is probably ten to fifteen million years older – vs. ) – and more closely contemporaneous with the fauna of the Maotianshan shales from Chengjiang, which are dated to .

Preservation

The preservation of the Sirius Passet is traditionally considered to represent silicification associated with a death mask, recalling the 'Ediacara-type' preservation of the Precambrian Ediacara biota. A 2022 study suggested that the original preservation mode was phosphatisation that was later altered by low-grade metamorphism with a peak temperature of 409 ± 50 C during the Devonian Ellesmerian orogeny, which resulted in widespread mineral replacement.

Geochemical analysis indicates that the fossils lived close to the boundary of an oxygen minimum zone, possibly being preserved in oxygen-starved periods.

IUGS geological heritage site

In respect of the importance of the exceptionally preserved fossils in our understanding of the event, the 'Cambrian Explosion in Sirius Passet' was included by the International Union of Geological Sciences (IUGS) in its assemblage of 100 'geological heritage sites' around the world in a listing published in October 2022. The organisation defines an 'IUGS Geological Heritage Site' as 'a key place with geological elements and/or processes of international scientific relevance, used as a reference, and/or with a substantial contribution to the development of geological sciences through history.'

Fauna

Although the fauna has not yet been fully described, it is known to consist of a moderate number of arthropods and sponges, and rare representatives of other groups. It has yielded the problematic taxon Halkieria, and the Panarthropods Kerygmachela and Pambdelurion, all of which have played prominent roles in discussions about the origins of the modern animal phyla.

Taxa from the Sirius Passet fauna

After

Arthropods

Other animals

References

References

1. (2011). "The extent of the Sirius Passet Lagerstätte (early Cambrian) of North Greenland". Bulletin of Geosciences.
2. (March 2010). "A new arthropod from the Early Cambrian of North Greenland, with a 'great appendage'-like antennula". [[Zoological Journal of the Linnean Society]].
3. (2016). "The Sirius Passet Lagerstätte: Silica death masking opens the window on the earliest matground community of the Cambrian explosion". Lethaia.
4. (2016). "Exceptional preservation of soft-bodied Ediacara Biota promoted by silica-rich oceans". Geology.
5. (2022-01-01). "Metamorphism obscures primary taphonomic pathways in the early Cambrian Sirius Passet Lagerstätte, North Greenland". Geology.
6. (2019). "The Sirius Passet Lagerstätte of North Greenland-A geochemical window on early Cambrian low-oxygen environments and ecosystems". Geobiology.
7. "The First 100 IUGS Geological Heritage Sites". IUGS.
8. Harper, David A. T.. (2019). "The Sirius Passet Lagerstätte of North Greenland: a remote window on the Cambrian Explosion". Journal of the Geological Society.
9. "A new Arthropod from the Lower Cambrian Sirius Passet Fossil-Lagerstätten of North Greenland". Bulletin of Geosciences.
10. Sun, Zhixin. (March 2020). "First occurrence of the Cambrian arthropod Sidneyia Walcott, 1911 outside of Laurentia". Geological Magazine.
11. (2011). "Vetulicolians from the Lower Cambrian Sirius Passet Lagerstätte, North Greenland, and the polarity of morphological characters in basal deuterostomes". Palaeontology.
12. Park, Tae-Yoon S.. (2024-01-05). "A giant stem-group chaetognath". Science Advances.
13. (25 July 2025). "A fossilized ventral ganglion reveals a chaetognath affinity for Cambrian nectocaridids". Science Advances.
14. (2008). "The Earliest Annelids: Lower Cambrian Polychaetes from the Sirius Passet Lagerstätte, Peary Land, North Greenland". Acta Palaeontologica Polonica.