Ediacaran

The Ediacaran ( /ˌiːdiˈækərən, ˌɛdi-/ EE-dee-AK-ər-ən, ED-ee-)[1] is a geological period of the Neoproterozoic Era that spans 96 million years from the end of the Cryogenian Period at 635 Mya to the beginning of the Cambrian Period at 538.8 Mya.Template:Ref icc It is the last period of the Proterozoic Eon as well as the last of the so-called "Precambrian supereon", before the beginning of the subsequent Cambrian Period marks the start of the Phanerozoic Eon, where recognizable fossil evidence of life becomes common.

The Ediacaran Period is named after the Ediacara Hills of South Australia, where trace fossils of a diverse community of previously unrecognized lifeforms (later named the Ediacaran biota) were first discovered by geologist Reg Sprigg in 1946.[2] Its status as an official geological period was ratified in 2004 by the International Union of Geological Sciences (IUGS), making it the first new geological period declared in 120 years.[3][4][5] Although the period took namesake from the Ediacara Hills in the Nilpena Ediacara National Park, the type section is actually located in the bed of the Enorama Creek[6] within the Brachina Gorge[7] in the Ikara-Flinders Ranges National Park, at  [ ⚑ ] 31°19′53.8″S 138°38′0.1″E﻿ / ﻿31.331611°S 138.633361°E﻿ / -31.331611; 138.633361, approximately 55 km (34 mi) southeast of the Ediacara Hills fossil site.

The Ediacaran marks the first widespread appearance of complex multicellular fauna following the end of the Cryogenian global glaciation known as the Snowball Earth. The relatively sudden evolutionary radiation event, known as the Avalon Explosion, is represented by now-extinct, relatively simple soft-bodied animal phyla such as Proarticulata (bilaterians with simple articulation, e.g. Dickinsonia and Spriggina), Petalonamae (sea pen-like animals, e.g. Charnia), Aspidella (radial-shaped animals, e.g. Cyclomedusa) and Trilobozoa (animals with tri-radial symmetry, e.g. Tribrachidium). Most of these organisms appeared during or after the Avalon explosion 575 million years ago and died out during the End-Ediacaran extinction event 539 million years ago. Forerunners of some modern animal phyla also appeared during this period, including cnidarians and early bilaterians, as well as mollusc-like Kimberella. Hard-bodied organisms with mineralized shells also began their fossil record in the last few million years of the Ediacaran.[8]

The supercontinent Pannotia formed and broke apart by the end of the period. The Ediacaran also witnessed several glaciation events, such as the Gaskiers and Baykonurian glaciations. The Shuram excursion also occurred during this period, but its glacial origin is unlikely.

## Contents

* 1 Ediacaran vs. Vendian
* 2 Upper and lower boundaries
* 3 Subdivisions
* 4 Absolute dating
* 5 Biota
* 6 Astronomical factors
* 7 Documentaries
* 8 See also
* 9 References
* 10 External links

## Ediacaran vs. Vendian

See also: Earth:Riphean (stage) and Jotnian

The Ediacaran Period overlaps but is shorter than the Vendian Period (650 to 543 million years ago), a name that was earlier, in 1952, proposed by Russian geologist and paleontologist Boris Sokolov. The Vendian concept was formed stratigraphically top-down, and the lower boundary of the Cambrian became the upper boundary of the Vendian.[9][10]

Paleontological substantiation of this boundary was worked out separately for the siliciclastic basin (base of the Baltic Stage of the Eastern European Platform[11]) and for the carbonate basin (base of the Tommotian stage of the Siberian Platform).[12] The lower boundary of the Vendian was suggested to be defined at the base of the Varanger (Laplandian stage) tillites.[10][13]

The Vendian in its type area consists of large subdivisions such as Laplandian, Redkino, Kotlin and Rovno regional stages with the globally traceable subdivisions and their boundaries, including its lower one.

The Redkino, Kotlin and Rovno regional stages have been substantiated in the type area of the Vendian on the basis of the abundant organic-walled microfossils, megascopic algae, metazoan body fossils and ichnofossils.[10][14]

The lower boundary of the Vendian could have a biostratigraphic substantiation as well taking into consideration the worldwide occurrence of the Pertatataka assemblage of giant acanthomorph acritarchs.[13]

## Upper and lower boundaries

The 'golden spike' (bronze disk in the lower section of the image) or 'type section' of the Global Boundary Stratotype Section and Point (GSSP) for the base of the Ediacaran System The 'golden spike' marking the GSSP

The Ediacaran Period (c. 635–538.8 Mya) represents the time from the end of global Marinoan glaciation to the first appearance worldwide of somewhat complicated trace fossils (Treptichnus pedum (Seilacher, 1955)).[4]

Although the Ediacaran Period does contain soft-bodied fossils, it is unusual in comparison to later periods because its beginning is not defined by a change in the fossil record. Rather, the beginning is defined at the base of a chemically distinctive carbonate layer that is referred to as a "cap carbonate", because it caps glacial deposits.

This bed is characterized by an unusual depletion of 13C that indicates a sudden climatic change at the end of the Marinoan ice age. The lower global boundary stratotype section (GSSP) of the Ediacaran is at the base of the cap carbonate (Nuccaleena Formation), immediately above the Elatina diamictite in the Enorama Creek section, Brachina Gorge, within the Ikara–Flinders Ranges National Park, Flinders Ranges, South Australia.

The GSSP of the upper boundary of the Ediacaran is the lower boundary of the Cambrian on the SE coast of Newfoundland approved by the International Commission on Stratigraphy as a preferred alternative to the base of the Tommotian Stage in Siberia which was selected on the basis of the ichnofossil Treptichnus pedum (Seilacher, 1955). In the history of stratigraphy it was the first case of usage of bioturbations for the System boundary definition.

Nevertheless, the definitions of the lower and upper boundaries of the Ediacaran on the basis of chemostratigraphy and ichnofossils are disputable.[13][15]

Cap carbonates generally have a restricted geographic distribution (due to specific conditions of their precipitation) and usually siliciclastic sediments laterally replace the cap carbonates in a rather short distance but cap carbonates do not occur above every tillite elsewhere[clarification needed] in the world.

The C-isotope chemostratigraphic characteristics obtained for contemporaneous cap carbonates in different parts of the world may be variable in a wide range owing to different degrees of secondary alteration of carbonates, dissimilar criteria used for selection of the least altered samples, and, as far as the C-isotope data are concerned, due to primary lateral variations of δ l3Ccarb in the upper layer of the ocean.[13][16]

Furthermore, Oman presents in its stratigraphic record a large negative carbon isotope excursion, within the Shuram[17] Formation that is clearly away from any glacial evidence[18] strongly questioning systematic association of negative δ l3Ccarb excursion and glacial events.[19] Also, the Shuram excursion is prolonged and is estimated to last for ~9.0 Myrs.[20]

As to the Treptichnus pedum, a reference ichnofossil for the lower boundary of the Cambrian, its usage for the stratigraphic detection of this boundary is always risky, because of the occurrence of very similar trace fossils belonging to the Treptichnids group well below the level of T. pedum in Namibia, Spain and Newfoundland, and possibly, in the western United States. The stratigraphic range of T. pedum overlaps the range of the Ediacaran fossils in Namibia, and probably in Spain.[13][21]

## Subdivisions

Outcrops of micaschists and marble of the Groupe de Canaveilles [fr; fr] (Ediacaran, c. 580 Ma) in the eastern Pyrenees (commune of Fontpédrouse, France)[22] Groupe de Canaveilles exposure (Piton de Castell Vidre) in the eastern Pyrenees (commune of Llo, France). 1 - Very silicious schist. 2 - Marble. 3 - Limestone and dolomite. 4 (& inset) - "Barégiennes" (thin, deformed, alternating calcareous/siliceous beds).[23]

The Ediacaran Period is not yet formally subdivided, but a proposed scheme[24] recognises an Upper Ediacaran whose base corresponds with the Gaskiers glaciation, a Terminal Ediacaran Stage starting around 550 million years ago, a preceding stage beginning around 575 Ma with the earliest widespread Ediacaran biota fossils; two proposed schemes differ on whether the lower strata should be divided into an Early and Middle Ediacaran or not, because it is not clear whether the Shuram excursion (which would divide the Early and Middle) is a separate event from the Gaskiers, or whether the two events are correlated.

## Absolute dating

The dating of the rock type section of the Ediacaran Period in South Australia has proven uncertain due to lack of overlying igneous material. Therefore, the age range of 635 to 538.8 million years is based on correlations to other countries where dating has been possible. The base age of approximately 635 million years is based on U–Pb (uranium–lead) and Re–Os (rhenium–osmium) dating from Africa, China, North America, and Tasmania.[25][26][27][28][29]

## Biota

Main article: Earth:Ediacaran biota

Archaeaspinus, a representative of phylum Proarticulata which also includes Dickinsonia, Karakhtia, Spriggina and numerous other organisms. They are members of the Ediacaran biota.[30]

The fossil record from most of the Ediacaran Period is sparse, as more easily fossilized hard-shelled animals did not evolve until the latest Ediacaran. The Ediacaran biota include the oldest definite multicellular organisms (with specialized tissues), the most common types of which resemble segmented worms, fronds, disks, or immobile bags. Among largely undisputed animals, Auroralumina and Haootia were cnidarians, while Yilingia represented the motile bilaterians.[31][32][33] Sponges recognisable as such also appeared, at latest, during the terminal Ediacaran, including Helicolocellus, a likely non-biomineralizing sponge.[34][35]

Other than these definitive animals, most members of the Ediacaran biota bear little resemblance to modern lifeforms, and their relationship with even the immediately following lifeforms of the Cambrian explosion is rather difficult to interpret.[36][37] More than 100 genera have been described, and well known forms include Arkarua, Charnia, Dickinsonia, Ediacaria, Marywadea, Cephalonega, Pteridinium, and Yorgia. However, despite the overall enigmaticness of most Ediacaran organisms, some fossils identifiable as hard-shelled agglutinated foraminifera (which are not classified as animals) are known from latest Ediacaran sediments of western Siberia.[38]

Four different biotic intervals are known in the Ediacaran, each being characterised by the prominence of a unique ecology and faunal assemblage. The first spanned from 635 to around 575 Ma and was dominated by acritarchs known as large ornamented Ediacaran microfossils.[39] The second spanned from around 575 to 560 Ma and was characterised by the Avalon biota. The third spanned from 560 to 550 Ma; its biota has been dubbed the White Sea biota due to many fossils from this time being found along the coasts of the White Sea. The fourth lasted from 550 to 539 Ma and is known as the interval of the Nama biotic assemblage.[40]

There is evidence for a mass extinction during this period from early animals changing the environment,[41] dating to the same time as the transition between the White Sea and the Nama-type biotas.[42][43] Alternatively, this mass extinction has also been theorised to have been the result of an anoxic event.[40]

## Astronomical factors

The relative proximity of the Moon at this time meant that tides were stronger and more rapid than they are now. The day was 21.9 ± 0.4 hours, and there were 13.1 ± 0.1 synodic months/year and 400 ± 7 solar days/year.[44]

## Documentaries

A few English language documentaries have featured the Ediacaran Period and biota:

* Australia: The Time Traveller's Guide (2012, ABC Science; Part 1 of 4).[45]
* The Geological History of Canada, as part of The Nature of Things series, CBC-SRC; 2011; Eastern Canada.
* The first episode of a BBC documentary titled Life on Earth, with David Attenborough as narrator.
* Another documentary narrated by David Attenborough titled First Life featuring Charnia, Dickinsonia, Spriggina, Funisia, and Kimberella animated in CGI.

## See also

* List of fossil sites (with link directory)
* Earth:Avalon explosion - Proposed evolutionary event in the history of metazoa, producing the Ediacaran biota
* Earth:End-Ediacaran extinction - Mass extinction event at the end of the Ediacaran period, 539 million years ago

## References

1. ↑ "Ediacaran". Dictionary.com Unabridged. Random House. https://www.dictionary.com/browse/Ediacaran.
2. ↑ Sprigg, Reg. C. (1947). "Early Cambrian (?) jellyfishes from the Flinders Ranges, South Australia". Transactions of the Royal Society of South Australia 71 (2): 212–224. https://www.biodiversitylibrary.org/page/41347851#page/234/mode/1up.
3. ↑ Cite error: Invalid `<ref>` tag; no text was provided for refs named `EP-Ediacaran`
4. ↑ 4.0 4.1 A. Knoll, M. Walter, G. Narbonne, and N. Christie-Blick (2004) "The Ediacaran Period: A New Addition to the Geologic Time Scale." Submitted on Behalf of the Terminal Proterozoic Subcommission of the International Commission on Stratigraphy.
5. ↑ Knoll, A. H.; Walter, MR; Narbonne, G. M; Christie-Blick, N (30 July 2004). "A new period for the geologic time scale". Science 305 (5684): 621–622. doi:10.1126/science.1098803. PMID 15286353. http://www.stratigraphy.org/bak/ediacaran/Knoll_et_al_2004b.pdf.
6. ↑ "Geological time gets a new period: Geologists have added a new period to their official calendar of Earth's history—the first in 120 years". London: BBC. 2004-05-17. https://news.bbc.co.uk/1/hi/sci/tech/3721481.stm. Accessed 27 December 2010.
7. ↑ South Australian Museum Newsletter April 2005 Accessed 9 August 2010.
8. ↑ Grant, S.W. (1990). "Shell structure and distribution of Cloudina, a potential index fossil for the terminal Proterozoic". American Journal of Science 290-A (290–A): 261–294. PMID 11538690. http://lib.bioinfo.pl/pmid:11538690. Retrieved 2008-07-19.
9. ↑ B. M. Sokolov (1952). "On the age of the old sedimentary cover of the Russian Platform". Izvestiya Akademii Nauk SSSR. Seriya Eologicheskaya 5: 21–31.
10. ↑ 10.0 10.1 10.2 Sokolov, B.S. (1997). "Essays on the Advent of the Vendian System." 153 pp. KMK Scientific Press, Moscow. (in Russian)
11. ↑ Sokolov B. S. (1965) "Abstracts of All-Union Symposium on Paleontology of the Precambrian and Early Cambrian." Nauka, Novosibirsk.
12. ↑ Rozanov, A.Y.; Missarzhevskij, V.V.; Volkova, N.A.; Voronova, L.G.; Krylov, I.N.; Keller, B.M.; Korolyuk, I.K.; Lendzion, K. et al. (1969). "The Tommotian Stage and the problem of the lower boundary of the Cambrian". Trudy Geologičeskogo Instituta AN SSSR 206: 1–380.
13. ↑ 13.0 13.1 13.2 13.3 13.4 "Vendian versus Ediacaran: priorities, contents, prospectives". 2007. http://vendian.net76.net/Vendian_vs_Ediacaran.htm. In: "The Rise and Fall of the Vendian (Ediacaran) Biota". Origin of the Modern Biosphere. Transactions of the International Conference on the IGCP Project 493n Moscow: GEOS. August 20–31, 2007. http://www.geosci.monash.edu.au/precsite/docs/workshop/moscow07/transaction.pdf. (82mb)
14. ↑ Khomentovsky, V. V. (2008). "The Yudomian of Siberia, Vendian and Ediacaran systems of the International stratigraphic scale". Stratigraphy and Geological Correlation 16 (6): 581–598. doi:10.1134/S0869593808060014. Bibcode: 2008SGC....16..581K.
15. ↑ Comments By B. S. Sokolov, M. A. Semikhatov, And M. A. Fedonkin. (2004) Appendix 2 in: "The Ediacaran Period: A New Addition to the Geologic Time Scale." Submitted on Behalf of the Terminal Proterozoic Subcommission of the International Commission on Stratigraphy. pp. 32–34
16. ↑ Bristow, T. F.; Kennedy, M. J. (2008). "Carbon isotope excursions and the oxidant budget of the Ediacaran atmosphere and ocean". Geology 36 (11): 863–866. doi:10.1130/G24968A.1. Bibcode: 2008Geo....36..863B. http://taylorandfrancis.metapress.com/index/PUNM6BQLNW1BJMFN.pdf. Retrieved 2007-05-05.
17. ↑ Le Guerroué, E.; Allen, P. A.; Cozzi, A. (2006). "Chemostratigraphic and sedimentological framework of the largest negative carbon isotopic excursion in Earth history: The Neoproterozoic Shuram Formation (Nafun Group, Oman).". Precambrian Research 146 (1–2): 68–92. doi:10.1016/j.precamres.2006.01.007. Bibcode: 2006PreR..146...68L.
18. ↑ Le Guerroué, E.; Allen, P. A.; Cozzi, A.; Etienne, J. L.; Fanning, C. M. (2006). "50 Myr recovery from the largest negative δ13C excursion in the Ediacaran ocean". Terra Nova 18 (2): 147–153. doi:10.1111/j.1365-3121.2006.00674.x. Bibcode: 2006TeNov..18..147L. http://www3.interscience.wiley.com/journal/118624047/abstract.
19. ↑ Le Guerroué, E.; Allen, P. A.; Cozzi, A. (2006). "Parasequence development in the Ediacaran Shuram Formation (Nafun Group, Oman): primary origin stratigraphic test of negative carbon isotopic ratios". Basin Research 18 (2): 205–220. doi:10.1111/j.1365-2117.2006.00292.x. Bibcode: 2006BasR...18..205L. http://www3.interscience.wiley.com/journal/118629748/abstract.
20. ↑ Gong, Zheng; Kodama, Kenneth; Li, Yong-Xiang (2017). "Rock magnetic cyclostratigraphy of the Doushantuo Formation, South China and its implications for the duration of the Shuram carbon isotope excursion". Precambrian Research 289: 62–74. doi:10.1016/j.precamres.2016.12.002. Bibcode: 2017PreR..289...62G.
21. ↑ A. Ragozina, D. Dorjnamjaa, A. Krayushkin, E. Serezhnikova (2008). "Treptichnus pedum and the Vendian-Cambrian boundary ". 33 Intern. Geol. Congr. August 6–14, 2008, Oslo, Norway. Abstracts. Section HPF 07 Rise and fall of the Ediacaran (Vendian) biota. P. 183.
22. ↑ B. Laumonier et al., Notice explicative de la feuille Prats-de-Mollo-La-preste (1099) à 1/50 000, BRGM Éditions, Orléans, 2015, pages 22-23 (bC1 - « ...niveau de marbres calcaires et dolomitiques M1...(dans les) hautes vallées de la Ribérole et de la Carança M1 est formé de 2 ou 3 niveaux décamétriques très continus.  », ficheinfoterre.brgm.fr.
23. ↑ "Sentier géologique de Llo, a journey through 600 million years of time". Parc naturel régional des Pyrénées catalanes. https://pnrpc.centredoc.fr/doc_num.php?explnum_id=457.
24. ↑ Xiao, Shuhai; Narbonne, Guy M.; Zhou, Chuanming; Laflamme, Marc; Grazhdankin, Dmitriy V.; Moczydlowska-Vidal, Malgorzata; Cui, Huan (2016). "Towards an Ediacaran Time Scale: Problems, Protocols, and Prospects". Episodes 39 (4): 540555. doi:10.18814/epiiugs/2016/v39i4/103886.
25. ↑ Rooney, Alan D.; Strauss, Justin V.; Brandon, Alan D.; Macdonald, Francis A. (2015). "A Cryogenian chronology: Two long-lasting synchronous Neoproterozoic glaciations" (in en). Geology 43 (5): 459–462. doi:10.1130/G36511.1. ISSN 1943-2682. Bibcode: 2015Geo....43..459R. http://pubs.geoscienceworld.org/geology/article/43/5/459/131888/A-Cryogenian-chronology-Two-longlasting.
26. ↑ Rooney, Alan D.; Yang, Chuan; Condon, Daniel J.; Zhu, Maoyan; Macdonald, Francis A. (2020-06-01). "U-Pb and Re-Os geochronology tracks stratigraphic condensation in the Sturtian snowball Earth aftermath" (in en). Geology 48 (6): 625–629. doi:10.1130/G47246.1. ISSN 0091-7613. Bibcode: 2020Geo....48..625R. https://pubs.geoscienceworld.org/gsa/geology/article/48/6/625/583510/UPb-and-ReOs-geochronology-tracks-stratigraphic.
27. ↑ Zhang, Shihong; Jiang, Ganqing; Zhang, Junming; Song, Biao; Kennedy, Martin J.; Christie-Blick, Nicholas (2005). "U-Pb sensitive high-resolution ion microprobe ages from the Doushantuo Formation in south China: Constraints on late Neoproterozoic glaciations" (in en). Geology 33 (6): 473. doi:10.1130/G21418.1. ISSN 0091-7613. Bibcode: 2005Geo....33..473Z. https://pubs.geoscienceworld.org/geology/article/33/6/473-476/103786.
28. ↑ Schmitz, M.D. (2012), "Radiometric ages used in GTS2012" (in en), The Geologic Time Scale (Elsevier): pp. 1045–1082, doi:10.1016/b978-0-444-59425-9.15002-4, ISBN 978-0-444-59425-9, https://linkinghub.elsevier.com/retrieve/pii/B9780444594259150024, retrieved 2022-04-02
29. ↑ Calver, C.R.; Crowley, J.L.; Wingate, M.T.D.; Evans, D.A.D.; Raub, T.D.; Schmitz, M.D. (2013). "Globally synchronous Marinoan deglaciation indicated by U-Pb geochronology of the Cottons Breccia, Tasmania, Australia" (in en). Geology 41 (10): 1127–1130. doi:10.1130/G34568.1. ISSN 1943-2682. Bibcode: 2013Geo....41.1127C. http://pubs.geoscienceworld.org/geology/article/41/10/1127/131079/Globally-synchronous-Marinoan-deglaciation.
30. ↑ Fedonkin, Mikhail A.; Gehling, James G.; Grey, Kathleen; Narbonne, Guy M.; Vickers-Rich, Patricia (Mar 16, 2007). The Rise of Animals: Evolution and Diversification of the Kingdom Animalia. JHU Press. ISBN 978-0-8018-8679-9. https://books.google.com/books?id=KsFFIrJ8IxEC&dq=Archaeaspinus&pg=PA261. Retrieved August 7, 2022.
31. ↑ Dunn, F. S.; Kenchington, C. G.; Parry, L. A.; Clark, J. W.; Kendall, R. S.; Wilby, P. R. (25 July 2022). "A crown-group cnidarian from the Ediacaran of Charnwood Forest, UK". Nature Ecology & Evolution 6 (8): 1095–1104. doi:10.1038/s41559-022-01807-x. PMID 35879540. Bibcode: 2022NatEE...6.1095D.
32. ↑ McIlroy, D.; Pasinetti, G.; Pérez-Pinedo, D.; McKean, C.; Dufour, S. C.; Matthews, J. J.; Menon, L. R.; Nicholls, R. et al. (2024-08-30). "The Palaeobiology of Two Crown Group Cnidarians: Haootia quadriformis and Mamsetia manunis gen. et sp. nov. from the Ediacaran of Newfoundland, Canada" (in en). Life 14 (9): 1096. doi:10.3390/life14091096. ISSN 2075-1729. PMID 39337880. Bibcode: 2024Life...14.1096M.
33. ↑ Chen, Zhe; Zhou, Chuanming; Yuan, Xunlai; Xiao, Shuhai (September 2019). "Death march of a segmented and trilobate bilaterian elucidates early animal evolution" (in en). Nature 573 (7774): 412–415. doi:10.1038/s41586-019-1522-7. ISSN 1476-4687. PMID 31485079. Bibcode: 2019Natur.573..412C. https://www.nature.com/articles/s41586-019-1522-7.
34. ↑ Xiao, Shuhai (12 August 2020). "Ediacaran sponges, animal biomineralization, and skeletal reefs" (in en). Proceedings of the National Academy of Sciences of the United States of America 117 (35): 20997–20999. doi:10.1073/pnas.2014393117. ISSN 0027-8424. PMID 32817471. Bibcode: 2020PNAS..11720997X.
35. ↑ Wang, Xiaopeng; Liu, Alexander G.; Chen, Zhe; Wu, Chengxi; Liu, Yarong; Wan, Bin; Pang, Ke; Zhou, Chuanming et al. (June 2024). "A late-Ediacaran crown-group sponge animal" (in en). Nature 630 (8018): 905–911. doi:10.1038/s41586-024-07520-y. ISSN 1476-4687. PMID 38839967. Bibcode: 2024Natur.630..905W. https://www.nature.com/articles/s41586-024-07520-y.
36. ↑ Xiao, Shuhai; Laflamme, Marc (January 2009). "On the eve of animal radiation: phylogeny, ecology and evolution of the Ediacara biota". Trends in Ecology & Evolution 24 (1): 31–40. doi:10.1016/j.tree.2008.07.015. PMID 18952316. Bibcode: 2009TEcoE..24...31X. https://www.sciencedirect.com/science/article/abs/pii/S0169534708003066. Retrieved 10 November 2022.
37. ↑ Dunn, Frances S.; Liu, Alexander G. (11 February 2019). "Viewing the Ediacaran biota as a failed experiment is unhelpful". Nature Ecology and Evolution 3 (4): 512–514. doi:10.1038/s41559-019-0815-4. PMID 30742104. Bibcode: 2019NatEE...3..512D. https://www.nature.com/articles/s41559-019-0815-4#citeas. Retrieved 10 November 2022.
38. ↑ Kontorovich, A. E.; Varlamov, A. I.; Grazhdankin, D. V.; Karlova, G. A.; Klets, A. G.; Kontorovich, V. A.; Saraev, S. V.; Terleev, A. A. et al. (2008-12-01). "A section of Vendian in the east of West Siberian Plate (based on data from the Borehole Vostok 3)" (in en). Russian Geology and Geophysics 49 (12): 932–939. doi:10.1016/j.rgg.2008.06.012. ISSN 1068-7971. Bibcode: 2008RuGG...49..932K. http://www.sciencedirect.com/science/article/pii/S106879710800206X.
39. ↑ Cohen, P. A.; Knoll, A. H.; Kodner, R. B. (Apr 2009). "Large spinose microfossils in Ediacaran rocks as resting stages of early animals". Proceedings of the National Academy of Sciences of the United States of America 106 (16): 6519–6524. doi:10.1073/pnas.0902322106. ISSN 0027-8424. PMID 19366668. Bibcode: 2009PNAS..106.6519C.
40. ↑ 40.0 40.1 Evans, Scott D.; Tu, Chenyi; Rizzo, Adriana; Surprenant, Rachel L.; Boan, Phillip C.; McCandless, Heather; Marshall, Nathan; Xiao, Shuhai et al. (7 November 2022). "Environmental drivers of the first major animal extinction across the Ediacaran White Sea-Nama transition". Proceedings of the National Academy of Sciences of the United States of America 119 (46). doi:10.1073/pnas.2207475119. PMID 36343248. PMC 9674242. Bibcode: 2022PNAS..11907475E. https://www.researchgate.net/publication/365204103. Retrieved 24 November 2023.
41. ↑ Laflamme, Marc; Darroch, Simon A. F.; Tweedt, Sarah M.; Peterson, Kevin J.; Erwin, Douglas H. (1 March 2013). "The end of the Ediacara biota: Extinction, biotic replacement, or Cheshire Cat?". Gondwana Research. Geological processes in the Early Earth 23 (2): 558–573. doi:10.1016/j.gr.2012.11.004. ISSN 1342-937X. Bibcode: 2013GondR..23..558L. https://www.sciencedirect.com/science/article/pii/S1342937X1200353X. Retrieved 24 November 2023.
42. ↑ Darroch, Simon A. F.; Sperling, Erik A.; Boag, Thomas H.; Racicot, Rachel A.; Mason, Sara J.; Morgan, Alex S.; Tweedt, Sarah; Myrow, Paul et al. (7 September 2015). "Biotic replacement and mass extinction of the Ediacara biota". Proceedings of the Royal Society B: Biological Sciences 282 (1814): 1–10. doi:10.1098/rspb.2015.1003. PMID 26336166. Bibcode: 2015RSPSB.28251003D.
43. ↑ Evidence that Earth's first mass extinction was caused by critters not catastrophe, ScienceDaily
44. ↑ Williams, George E. (2000). "Geological constraints on the Precambrian history of Earth's rotation and the Moon's orbit". Reviews of Geophysics 38 (1): 37–60. doi:10.1029/1999RG900016. Bibcode: 2000RvGeo..38...37W.
45. ↑ Celebrating 50 years of ABC Science Retrieved 18 March 2023.

## External links

* "Geological time gets a new period: Geologists have added a new period to their official calendar of Earth's history—the first in 120 years". London: BBC. 2004-05-17. https://news.bbc.co.uk/1/hi/sci/tech/3721481.stm.
* "Ediacaran Period". GeoWhen Database. http://www.stratigraphy.org/bak/geowhen/stages/Ediacaran.html.
* Introduction to the Vendian Period
* transcript – Catalyst (Australian Broadcasting Corporation)
* Mistaken Point Fauna: The Discovery
* Earth's oldest animal ecosystem held in fossils at Nilpena Station in SA outback ABC News, 5 August 2013. Accessed 6 August 2013.
* Australia: The Time Traveller's Guide (2012) on IMDb
* In Our Time – Ediacara Biota, BBC Radio, 9 July 2009. Accessed 1 February 2025.

Template:Proterozoic footer

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Geological history of Earth

Cenozoic era
(present–66.0 Mya)|

| Quaternary (present–2.588 Mya)|

* Holocene (present–11.784 kya)
* Pleistocene (11.784 kya–2.588 Mya)

|

Neogene (2.588–23.03 Mya)|

* Pliocene (2.588–5.333 Mya)
* Miocene (5.333–23.03 Mya)

Paleogene (23.03–66.0 Mya)|

* Oligocene (23.03–33.9 Mya)
* Eocene (33.9–56.0 Mya)
* Paleocene (56.0–66.0 Mya)

Mesozoic era
(66.0–251.902 Mya)|

| Cretaceous (66.0–145.0 Mya)|

* Late (66.0–100.5 Mya)
* Early (100.5–145.0 Mya)

|

Jurassic (145.0–201.3 Mya)|

* Late (145.0–163.5 Mya)
* Middle (163.5–174.1 Mya)
* Early (174.1–201.3 Mya)

Triassic (201.3–251.902 Mya)|

* Late (201.3–237 Mya)
* Middle (237–247.2 Mya)
* Early (247.2–251.902 Mya)

Paleozoic era
(251.902–541.0 Mya)|

| Permian (251.902–298.9 Mya)|

* Lopingian (251.902–259.8 Mya)
* Guadalupian (259.8–272.3 Mya)
* Cisuralian (272.3–298.9 Mya)

|

Carboniferous (298.9–358.9 Mya)|

* Pennsylvanian (298.9–323.2 Mya)
* Mississippian (323.2–358.9 Mya)

Devonian (358.9–419.2 Mya)|

* Late (358.9–382.7 Mya)
* Middle (382.7–393.3 Mya)
* Early (393.3–419.2 Mya)

Silurian (419.2–443.8 Mya)|

* Pridoli (419.2–423.0 Mya)
* Ludlow (423.0–427.4 Mya)
* Wenlock (427.4–433.4 Mya)
* Llandovery (433.4–443.8 Mya)

Ordovician (443.8–485.4 Mya)|

* Late (443.8–458.4 Mya)
* Middle (458.4–470.0 Mya)
* Early (470.0–485.4 Mya)

Cambrian (485.4–541.0 Mya)|

* Furongian (485.4–497 Mya)
* Miaolingian (497–509 Mya)
* Series 2 (509–521 Mya)
* Terreneuvian (521–541.0 Mya)

Proterozoic eon
(541.0 Mya–2.5 Gya)|

| Neoproterozoic (541.0 Mya–1 Gya)|

* Ediacaran (541.0–~635 Mya)
* Cryogenian (~635–~720 Mya)
* Tonian (~720 Mya–1 Gya)

|

Mesoproterozoic (1–1.6 Gya)|

* Stenian (1–1.2 Gya)
* Ectasian (1.2–1.4 Gya)
* Calymmian (1.4–1.6 Gya)

Paleoproterozoic (1.6–2.5 Gya)|

* Statherian (1.6–1.8 Gya)
* Orosirian (1.8–2.05 Gya)
* Rhyacian (2.05–2.3 Gya)
* Siderian (2.3–2.5 Gya)

Archean eon (2.5–4 Gya)|

| Eras|

* Neoarchean (2.5–2.8 Gya)
* Mesoarchean (2.8–3.2 Gya)
* Paleoarchean (3.2–3.6 Gya)
* Eoarchean (3.6–4 Gya)

|

Hadean eon (4–4.6 Gya)|

|  |

|

kya = thousands years ago. Mya = millions years ago. Gya = billions years ago.
See also: Geologic time scale

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