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- Ineson, Jon R., et al.
(author)
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Geological and depositional setting of the Sirius Passet Lagerstatte (Early Cambrian), North Greenland
- 2011
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In: Canadian journal of earth sciences (Print). - 0008-4077 .- 1480-3313. ; 48:8, s. 1259-1281
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Journal article (peer-reviewed)abstract
- The Early Cambrian Sirius Passet Lagerstatte of North Greenland occurs in marine mudstones (Buen Formation) deposited in a slope environment along the eroded scarp of a pre-existing carbonate platform. The shallow-water platform is represented by dolostones of the Portfjeld Formation (Neoproterozoic - earliest Cambrian), which record a belt of tide-swept subtidal ooid shoals and microbial patch reefs at the outer edge of the platform. Solution features and meteoric cements attest to exposure of the platform, accompanied by fracturing, mass wastage and erosional retreat of the escarpment producing slope talus, and extensive debris sheets and olistoliths in basinal deposits. The marine mud-dominated siliciclastics of the Buen Formation, deposited in slope and shelf environments, record the transgression and onlap of the degraded platform in the Early Cambrian. The Sirius Passet Lagerstatte has yielded an arthropod-dominated fossil assemblage of over 40 species, many showing exceptional preservation of soft tissues; the finely laminated mudstones hosting this fauna accumulated from suspension in a poorly oxygenated slope sub-environment, such as an erosional embayment or abandoned slope gully. Although taphonomic features suggest that the fauna is mainly parautochthonous, some components (e. g., sponges, worms, the halkieriids and certain sightless arthropods) may be truly autochthonous. Comparison of the Sirius Passet locality with the renowned Middle Cambrian Burgess Shale of western Canada reveals similarities in overall depositional and tectonic setting: both accumulated in deep water adjacent to the steep, eroded margins of carbonate platforms - settings that subsequently sheltered the faunas from tectonic and metamorphic obliteration.
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- Peel, John S., et al.
(author)
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The extent of the Sirius Passet Lagerstatte (early Cambrian) of North Greenland
- 2011
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In: Bulletin of Geosciences. - : Czech Geological Survey. - 1214-1119 .- 1802-8225. ; 86:3, s. 535-543
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Journal article (peer-reviewed)abstract
- Ancillary localities for the Sirius Passet biota (early Cambrian; Cambrian Series 2, Stage 3) are described from the immediate vicinity of the main locality on the southern side of Sirius Passet, north-western Peary Land, central North Greenland, where slope mudstones of the Transitional Buen Formation abut against the margin of the Portfjeld Formation carbonate platform. Whilst this geological relationship may extend over more than 500 km east-west across North Greenland, known exposures of the sediments yielding the lagerst tte are restricted to a 1 km long window at the south-western end of Sirius Passet.
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- Willman, Sebastian, Docent, et al.
(author)
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Ediacaran Doushantuo-type biota discovered in Laurentia
- 2020
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In: Communications Biology. - : Springer Science and Business Media LLC. - 2399-3642. ; 3:1
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Journal article (peer-reviewed)abstract
- The Ediacaran period (635-541 Ma) was a time of major environmental change, accompanied by a transition from a microbial world to the animal world we know today. Multicellular, macroscopic organisms preserved as casts and molds in Ediacaran siliciclastic rocks are preserved worldwide and provide snapshots of early organismal, including animal, evolution. Remarkable evolutionary advances are also witnessed by diverse cellular and subcellular phosphatized microfossils described from the Doushantuo Formation in China, the only source showing a diversified assemblage of microfossils. Here, we greatly extend the known distribution of this Doushantuo-type biota in reporting an Ediacaran Lagerstätte from Laurentia (Portfjeld Formation, North Greenland), with phosphatized animal-like eggs, embryos, acritarchs, and cyanobacteria, the age of which is constrained by the Shuram-Wonoka anomaly (c. 570-560 Ma). The discovery of these Ediacaran phosphatized microfossils from outside East Asia extends the distribution of the remarkable biota to a second palaeocontinent in the other hemisphere of the Ediacaran world, considerably expanding our understanding of the temporal and environmental distribution of organisms immediately prior to the Cambrian explosion.
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