Earth:Terreneuvian

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The Terreneuvian or Early Cambrian is the lowermost and oldest series of the Cambrian geological system.[1] Its base is defined by the first appearance datum of the trace fossil Treptichnus pedum around 541 million years ago. Its top is defined as the first appearance of trilobites in the stratigraphic record around 521 million years ago.[2] This series' name was formally accepted by the International Commission on Stratigraphy in 2007.[1]

The Fortunian stage and presently unnamed Cambrian Stage 2 are the stages within this series. The Terreneuvian corresponds to the pre-trilobitic Cambrian.[3]

The name Terreneuvian is derived from Terre Neuve, the French name for the island of Newfoundland, Canada, where many rocks of this age are found, including the type section.[1][2]

GSSP

The type locality (GSSP) of the Terreneuvian is in Fortune Head, at the northern edge of the Burin Peninsula, Newfoundland, Canada ( [ ⚑ ] 47°04′34″N 55°49′52″W / 47.0762°N 55.8310°W / 47.0762; -55.8310). The outcrops show a carbonate-siliciclastic succession which is mapped as the Chapel Island Formation. The formation is divided into the following members that are composed of peritidal sandstones and shales (Member 1), muddy deltaic and shelf sandstones and mudstones (Member 2A), laminated siltstones (Member 2B and 3) and mudstones and limestones of the inner shelf (Member 4). The Precambrian-Cambrian boundary lies 2.4 m above the base of the second member, which is the lowest occurrence of Treptichnus pedum. The traces can be seen on the lower surface of the sandstone layers. The first calcareous shelled skeletal fossils (Ladatheca cylindrica) are 400 m above the boundary. The first trilobites appear 1400 m above the boundary, which corresponds to the beginning of the Branchian Series (Series 2).[4]

Major events

The second phase of the Cambrian explosion occurs during the Terreneuvian. Lots of lophotrochozoan and calcified basal metazoan lineages appeared in this epoch. However, deuterostomes are absent in this interval,[5] with the possible exception of Yanjiahella from the Fortunian.[6]

See also

  • Stratigraphy of the Cambrian

References

  1. ↑ 1.0 1.1 1.2 Cite error: Invalid <ref> tag; no text was provided for refs named EP-Fortunian
  2. ↑ 2.0 2.1 Shan-Chi Peng, Babcock Loren (2011). "Continuing progress on chronostratigraphic subdivision of the Cambrian System". Bulletin of Geosciences 86 (3): 391–396. doi:10.3140/bull.geosci.1273. ISSN 1214-1119. http://www.geology.cz/bulletin/fulltext/1273_Peng.pdf. 
  3. ↑ Li, G.. "The Fad of Watsonella Crosbyi". http://www.casp.cam.ac.uk/meetings/meeting-20110612. 
  4. ↑ Brasier, Martin; John Cowie; Michael Taylor (1994). "Decision on the Precambrian-Cambrian boundary stratotype". Episodes 17 (1–2): 95–100. doi:10.18814/epiiugs/1994/v17i1.2/002. https://timescalefoundation.org/references/Fortunian0.pdf. Retrieved 2024-03-31. 
  5. ↑ Degan Shu, Yukio Isozaki, Xingliang Zhang, Jan Han, Shigenori Maruyama (2014). "Birth and early evolution of metazoans". Gondwana Research 25 (3): 884–895. doi:10.1016/j.gr.2013.09.001. Bibcode: 2014GondR..25..884S. https://www.researchgate.net/publication/260167495. 
  6. ↑ Zamora, Samuel; Wright, David F.; Mooi, Rich; Lefebvre, Bertrand; Guensburg, Thomas E.; Gorzelak, Przemysław; David, Bruno; Sumrall, Colin D. et al. (2020-03-09). "Re-evaluating the phylogenetic position of the enigmatic early Cambrian deuterostome Yanjiahella" (in en). Nature Communications 11 (1): 1286. doi:10.1038/s41467-020-14920-x. ISSN 2041-1723. PMID 32152310. Bibcode: 2020NatCo..11.1286Z. 

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