ediacaran

{{See also|Riphean (stage)|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.{{cite journal

| author = B. M. Sokolov

| year = 1952

| title = On the age of the old sedimentary cover of the Russian Platform

| journal = Izvestiya Akademii Nauk SSSR, Seriya Eologicheskaya

| volume = 5

| pages = 21–31

}}Sokolov, B.S. (1997). "Essays on the Advent of the Vendian System." 153 pp. KMK Scientific Press, Moscow. (in Russian)

Paleontological substantiation of this boundary was worked out separately for the siliciclastic basin (base of the Baltic Stage of the Eastern European PlatformSokolov B. S. (1965) "Abstracts of All-Union Symposium on Paleontology of the Precambrian and Early Cambrian." Nauka, Novosibirsk.) and for the carbonate basin (base of the Tommotian stage of the Siberian Platform).{{cite journal

|author1=Rozanov, A.Y. |author2=Missarzhevskij, V.V. |author3=Volkova, N.A. |author4=Voronova, L.G. |author5=Krylov, I.N. |author6=Keller, B.M. |author7=Korolyuk, I.K. |author8=Lendzion, K. |author9=Michniak, R. |author10=Pykhova, N.G. |author11= Sidorov, A.D. |name-list-style=amp| year = 1969

| title = The Tommotian Stage and the problem of the lower boundary of the Cambrian

| journal = Trudy Geologičeskogo Instituta AN SSSR

| volume = 206

| pages = 1–380

}}

The lower boundary of the Vendian was suggested to be defined at the base of the Varanger (Laplandian stage) tillites.{{cite web |url=http://vendian.net76.net/Vendian_vs_Ediacaran.htm |title=Vendian versus Ediacaran: priorities, contents, prospectives |author1=M. A. Fedonkin |author2=B. S. Sokolov |author3=M. A. Semikhatov |author4=N. M. Chumakov |year=2007 |url-status=dead |archive-url=https://web.archive.org/web/20111004184527/http://vendian.net76.net/Vendian_vs_Ediacaran.htm |archive-date=October 4, 2011 }} In: {{cite web |url=http://www.geosci.monash.edu.au/precsite/docs/workshop/moscow07/transaction.pdf |title=The Rise and Fall of the Vendian (Ediacaran) Biota |date=August 20–31, 2007 |work=Origin of the Modern Biosphere. Transactions of the International Conference on the IGCP Project 493n Moscow: GEOS |archive-url=https://web.archive.org/web/20121122062305/http://www.geosci.monash.edu.au/precsite/docs/workshop/moscow07/transaction.pdf |archive-date=22 November 2012 |url-status=dead }} (82mb)

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.{{Cite journal| doi = 10.1134/S0869593808060014| title = The Yudomian of Siberia, Vendian and Ediacaran systems of the International stratigraphic scale| year = 2008| last1 = Khomentovsky | first1 = V. V.| journal = Stratigraphy and Geological Correlation| volume = 16| issue = 6| pages = 581–598 |bibcode = 2008SGC....16..581K | s2cid = 128966206}}

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.

File:Ediacaran-GSSP-IMGP6652-.jpg (GSSP) for the base of the Ediacaran System]]

File:Ediacaran GSSP - closeup.JPG

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)).A. Knoll, M. Walter, G. Narbonne, and N. Christie-Blick (2004) "[http://www.stratigraphy.org/bak/ediacaran/Knoll_et_al_2004a.pdf 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.

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, 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.Comments By B. S. Sokolov, M. A. Semikhatov, And M. A. Fedonkin. (2004) Appendix 2 in: "[http://www.stratigraphy.org/bak/ediacaran/Knoll_et_al_2004a.pdf 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

Cap carbonates generally have a restricted geographic distribution (due to specific conditions of their precipitation){{vague|date=June 2013}} and usually siliciclastic sediments laterally replace the cap carbonates in a rather short distance but cap carbonates do not occur above every tillite elsewhere{{clarify|reason=location not specified|date=May 2013}} 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 ^l3C_carb in the upper layer of the ocean.{{cite journal

|author1 = Bristow, T. F.

|author2 = Kennedy, M. J.

|year = 2008

|title = Carbon isotope excursions and the oxidant budget of the Ediacaran atmosphere and ocean

|journal = Geology

|volume = 36

|issue = 11

|pages = 863–866

|url = http://taylorandfrancis.metapress.com/index/PUNM6BQLNW1BJMFN.pdf

|access-date = 2007-05-05

|doi = 10.1130/G24968A.1

|bibcode = 2008Geo....36..863B

|archive-date = 7 May 2020

|archive-url = https://web.archive.org/web/20200507214320/http://taylorandfrancis.metapress.com/index/PUNM6BQLNW1BJMFN.pdf

|url-status = dead

}}

Furthermore, Oman presents in its stratigraphic record a large negative carbon isotope excursion, within the Shuram{{cite journal

|author1=Le Guerroué, E. |author2=Allen, P. A. |author3=Cozzi, A. | year = 2006

| title =Chemostratigraphic and sedimentological framework of the largest negative carbon isotopic excursion in Earth history: The Neoproterozoic Shuram Formation (Nafun Group, Oman).

| journal = Precambrian Research

| volume = 146

| issue = 1–2

| pages = 68–92

| doi = 10.1016/j.precamres.2006.01.007

|bibcode=2006PreR..146...68L}} Formation that is clearly away from any glacial evidence{{cite journal

| author = Le Guerroué, E. |author2=Allen, P. A. |author3=Cozzi, A. |author4=Etienne, J. L. |author5=Fanning, C. M.

| year = 2006

| title =50 Myr recovery from the largest negative δ¹³C excursion in the Ediacaran ocean

| journal = Terra Nova

| volume = 18

| issue = 2

| pages = 147–153

| doi = 10.1111/j.1365-3121.2006.00674.x

| url = http://www3.interscience.wiley.com/journal/118624047/abstract

| archive-url = https://archive.today/20130105074949/http://www3.interscience.wiley.com/journal/118624047/abstract

| url-status = dead

| archive-date = 2013-01-05

|bibcode=2006TeNov..18..147L|s2cid=140710102 }} strongly questioning systematic association of negative δ ^l3C_carb excursion and glacial events.{{cite journal

| author = Le Guerroué, E.

|author2=Allen, P. A. |author3=Cozzi, A.

| year = 2006

| title =Parasequence development in the Ediacaran Shuram Formation (Nafun Group, Oman): primary origin stratigraphic test of negative carbon isotopic ratios

| journal = Basin Research

| volume = 18

| pages = 205–220

| doi = 10.1111/j.1365-2117.2006.00292.x

| url = http://www3.interscience.wiley.com/journal/118629748/abstract

| archive-url = https://archive.today/20130105102240/http://www3.interscience.wiley.com/journal/118629748/abstract

| url-status = dead

| archive-date = 2013-01-05

| issue = 2

| bibcode =2006BasR...18..205L|s2cid=128910191 }} Also, the Shuram excursion is prolonged and is estimated to last for ~9.0 Myrs.{{Cite journal|title=Rock magnetic cyclostratigraphy of the Doushantuo Formation, South China and its implications for the duration of the Shuram carbon isotope excursion|last1=Gong|first1=Zheng|last2=Kodama|first2=Kenneth|year=2017|last3=Li|first3=Yong-Xiang|doi=10.1016/j.precamres.2016.12.002|volume=289|journal=Precambrian Research|pages=62–74|bibcode=2017PreR..289...62G}}

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.A. Ragozina, D. Dorjnamjaa, A. Krayushkin, E. Serezhnikova (2008). "[http://vendian.net76.net/Treptichnus_pedum.htm Treptichnus pedum and the Vendian-Cambrian boundary] {{Webarchive|url=https://web.archive.org/web/20111004184532/http://vendian.net76.net/Treptichnus_pedum.htm |date=4 October 2011 }}". 33 Intern. Geol. Congr. August 6–14, 2008, Oslo, Norway. Abstracts. Section HPF 07 Rise and fall of the Ediacaran (Vendian) biota. P. 183.

[[File:Nou Fonts Ediacaran.jpg|thumb|

Outcrops of Ediacaran micaschists and marble (c. 600 Ma) in the eastern Pyrenees (commune of Fontpédrouse, France).B. Laumonier et al., [http://ficheinfoterre.brgm.fr/Notices/1099N.pdf 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.]]

The Ediacaran Period is not yet formally subdivided, but a proposed scheme{{cite journal | title=Towards an Ediacaran Time Scale: Problems, Protocols, and Prospects | first1=Shuhai | last1=Xiao | first2=Guy M. | last2=Narbonne | first3=Chuanming | last3=Zhou | first4=Marc | last4=Laflamme | first5=Dmitriy V. | last5=Grazhdankin | first6=Malgorzata | last6=Moczydlowska-Vidal | first7=Huan | last7=Cui | journal=Episodes | year=2016 | volume=39 | issue=4 | pages=540555 | doi=10.18814/epiiugs/2016/v39i4/103886 | doi-access=free }} recognises an Upper Ediacaran whose base corresponds with the Gaskiers glaciation, a Terminal Ediacaran Stage starting around {{Ma|550}}, 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.

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.{{Cite journal |last1=Rooney |first1=Alan D. |last2=Strauss |first2=Justin V. |last3=Brandon |first3=Alan D. |last4=Macdonald |first4=Francis A. |date=2015 |title=A Cryogenian chronology: Two long-lasting synchronous Neoproterozoic glaciations |url=http://pubs.geoscienceworld.org/geology/article/43/5/459/131888/A-Cryogenian-chronology-Two-longlasting |journal=Geology |language=en |volume=43 |issue=5 |pages=459–462 |doi=10.1130/G36511.1 |bibcode=2015Geo....43..459R |issn=1943-2682}}{{Cite journal |last1=Rooney |first1=Alan D. |last2=Yang |first2=Chuan |last3=Condon |first3=Daniel J. |last4=Zhu |first4=Maoyan |last5=Macdonald |first5=Francis A. |date=2020-06-01 |title=U-Pb and Re-Os geochronology tracks stratigraphic condensation in the Sturtian snowball Earth aftermath |url=https://pubs.geoscienceworld.org/gsa/geology/article/48/6/625/583510/UPb-and-ReOs-geochronology-tracks-stratigraphic |journal=Geology |language=en |volume=48 |issue=6 |pages=625–629 |doi=10.1130/G47246.1 |bibcode=2020Geo....48..625R |s2cid=218815302 |issn=0091-7613}}{{Cite journal |last1=Zhang |first1=Shihong |last2=Jiang |first2=Ganqing |last3=Zhang |first3=Junming |last4=Song |first4=Biao |last5=Kennedy |first5=Martin J. |last6=Christie-Blick |first6=Nicholas |date=2005 |title=U-Pb sensitive high-resolution ion microprobe ages from the Doushantuo Formation in south China: Constraints on late Neoproterozoic glaciations |url=https://pubs.geoscienceworld.org/geology/article/33/6/473-476/103786 |journal=Geology |language=en |volume=33 |issue=6 |pages=473 |doi=10.1130/G21418.1 |bibcode=2005Geo....33..473Z |issn=0091-7613}}{{Citation |last=Schmitz |first=M.D. |title=Radiometric ages used in GTS2012 |date=2012 |url=https://linkinghub.elsevier.com/retrieve/pii/B9780444594259150024 |work=The Geologic Time Scale |pages=1045–1082 |publisher=Elsevier |language=en |doi=10.1016/b978-0-444-59425-9.15002-4 |isbn=978-0-444-59425-9 |access-date=2022-04-02}}{{Cite journal |last1=Calver |first1=C.R. |last2=Crowley |first2=J.L. |last3=Wingate |first3=M.T.D. |last4=Evans |first4=D.A.D. |last5=Raub |first5=T.D. |last6=Schmitz |first6=M.D. |date=2013 |title=Globally synchronous Marinoan deglaciation indicated by U-Pb geochronology of the Cottons Breccia, Tasmania, Australia |url=http://pubs.geoscienceworld.org/geology/article/41/10/1127/131079/Globally-synchronous-Marinoan-deglaciation |journal=Geology |language=en |volume=41 |issue=10 |pages=1127–1130 |doi=10.1130/G34568.1 |bibcode=2013Geo....41.1127C |issn=1943-2682}}

{{Main|Ediacaran biota}}

File:Archaeaspinus_fedonkini.jpg, a representative of phylum Proarticulata which also includes Dickinsonia, Karakhtia and numerous other organisms. They are members of the Ediacaran biota.{{Cite book|url=https://books.google.com/books?id=KsFFIrJ8IxEC&dq=Archaeaspinus&pg=PA261|title=The Rise of Animals: Evolution and Diversification of the Kingdom Animalia|first1=Mikhail A.|last1=Fedonkin |first2=James G.|last2=Gehling |first3=Kathleen|last3=Grey|first4=Guy M.|last4=Narbonne|first5=Patricia|last5=Vickers-Rich |date=Mar 16, 2007|publisher=JHU Press|isbn=9780801886799|access-date=August 7, 2022|via=Google Books}}]]

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.{{cite journal |last1=Dunn |first1=F. S. |last2=Kenchington |first2=C. G. |last3=Parry |first3=L. A. |last4=Clark |first4=J. W. |last5=Kendall |first5=R. S. |last6=Wilby |first6=P. R. |title=A crown-group cnidarian from the Ediacaran of Charnwood Forest, UK |journal=Nature Ecology & Evolution |date=25 July 2022 |volume=6 |issue=8 |pages=1095–1104 |doi=10.1038/s41559-022-01807-x |pmid=35879540 |pmc=9349040 |bibcode=2022NatEE...6.1095D }}{{Cite journal |last1=McIlroy |first1=D. |last2=Pasinetti |first2=G. |last3=Pérez-Pinedo |first3=D. |last4=McKean |first4=C. |last5=Dufour |first5=S. C. |last6=Matthews |first6=J. J. |last7=Menon |first7=L. R. |last8=Nicholls |first8=R. |last9=Taylor |first9=R. S. |date=2024-08-30 |title=The Palaeobiology of Two Crown Group Cnidarians: Haootia quadriformis and Mamsetia manunis gen. et sp. nov. from the Ediacaran of Newfoundland, Canada |journal=Life |language=en |volume=14 |issue=9 |pages=1096 |doi=10.3390/life14091096 |doi-access=free |pmid=39337880 |bibcode=2024Life...14.1096M |issn=2075-1729 |pmc=11432848 }}{{Cite journal |last1=Chen |first1=Zhe |last2=Zhou |first2=Chuanming |last3=Yuan |first3=Xunlai |last4=Xiao |first4=Shuhai |date=September 2019 |title=Death march of a segmented and trilobate bilaterian elucidates early animal evolution |url=https://www.nature.com/articles/s41586-019-1522-7 |journal=Nature |language=en |volume=573 |issue=7774 |pages=412–415 |doi=10.1038/s41586-019-1522-7 |pmid=31485079 |bibcode=2019Natur.573..412C |issn=1476-4687}} Sponges recognisable as such also appeared, at latest, during the terminal Ediacaran, including Helicolocellus, a likely non-biomineralizing sponge. {{Cite journal |last=Xiao |first=Shuhai |date=12 August 2020 |title=Ediacaran sponges, animal biomineralization, and skeletal reefs |journal=Proceedings of the National Academy of Sciences of the United States of America |language=en |volume=117 |issue=35 |pages=20997–20999 |bibcode=2020PNAS..11720997X |doi=10.1073/pnas.2014393117 |issn=0027-8424 |pmc=7474584 |pmid=32817471 |doi-access=free}}{{Cite journal |last1=Wang |first1=Xiaopeng |last2=Liu |first2=Alexander G. |last3=Chen |first3=Zhe |last4=Wu |first4=Chengxi |last5=Liu |first5=Yarong |last6=Wan |first6=Bin |last7=Pang |first7=Ke |last8=Zhou |first8=Chuanming |last9=Yuan |first9=Xunlai |last10=Xiao |first10=Shuhai |date=June 2024 |title=A late-Ediacaran crown-group sponge animal |url=https://www.nature.com/articles/s41586-024-07520-y |journal=Nature |language=en |volume=630 |issue=8018 |pages=905–911 |doi=10.1038/s41586-024-07520-y |pmid=38839967 |bibcode=2024Natur.630..905W |issn=1476-4687}}

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.{{cite journal |last1=Xiao |first1=Shuhai |last2=Laflamme |first2=Marc |date=January 2009 |title=On the eve of animal radiation: phylogeny, ecology and evolution of the Ediacara biota |url=https://www.sciencedirect.com/science/article/abs/pii/S0169534708003066 |journal=Trends in Ecology & Evolution |volume=24 |issue=1 |pages=31–40 |doi=10.1016/j.tree.2008.07.015 |pmid=18952316 |bibcode=2009TEcoE..24...31X |access-date=10 November 2022}}{{cite journal |last1=Dunn |first1=Frances S. |last2=Liu |first2=Alexander G. |date=11 February 2019 |title=Viewing the Ediacaran biota as a failed experiment is unhelpful |url=https://www.nature.com/articles/s41559-019-0815-4#citeas |journal=Nature Ecology and Evolution |volume=3 |issue=4 |pages=512–514 |doi=10.1038/s41559-019-0815-4 |pmid=30742104 |bibcode=2019NatEE...3..512D |s2cid=59945361 |access-date=10 November 2022}} 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.{{Cite journal|last1=Kontorovich|first1=A. E.|last2=Varlamov|first2=A. I.|last3=Grazhdankin|first3=D. V.|last4=Karlova|first4=G. A.|last5=Klets|first5=A. G.|last6=Kontorovich|first6=V. A.|last7=Saraev|first7=S. V.|last8=Terleev|first8=A. A.|last9=Belyaev|first9=S. Yu.|last10=Varaksina|first10=I. V.|last11=Efimov|first11=A. S.|date=2008-12-01|title=A section of Vendian in the east of West Siberian Plate (based on data from the Borehole Vostok 3)|url=http://www.sciencedirect.com/science/article/pii/S106879710800206X|journal=Russian Geology and Geophysics|language=en|volume=49|issue=12|pages=932–939|doi=10.1016/j.rgg.2008.06.012|bibcode=2008RuGG...49..932K|issn=1068-7971}}

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.{{Cite journal | first1=P. A.| last2= Knoll| last3= Kodner | first2=A. H.| last1 = Cohen | first3=R. B.| journal = Proceedings of the National Academy of Sciences of the United States of America| volume = 106| title = Large spinose microfossils in Ediacaran rocks as resting stages of early animals| issue = 16| pages = 6519–6524| date=Apr 2009 | issn = 0027-8424| pmid = 19366668| pmc = 2672526| doi = 10.1073/pnas.0902322106 |bibcode = 2009PNAS..106.6519C | doi-access= free}} 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.{{cite journal |last1=Evans |first1=Scott D. |last2=Tu |first2=Chenyi |last3=Rizzo |first3=Adriana |last4=Surprenant |first4=Rachel L. |last5=Boan |first5=Phillip C. |last6=McCandless |first6=Heather |last7=Marshall |first7=Nathan |last8=Xiao |first8=Shuhai |last9=Droser |first9=Mary L. |date=7 November 2022 |title=Environmental drivers of the first major animal extinction across the Ediacaran White Sea-Nama transition |url=https://www.researchgate.net/publication/365204103 |journal=Proceedings of the National Academy of Sciences of the United States of America |volume=119 |issue=46 |pages=e2207475119 |bibcode=2022PNAS..11907475E |doi=10.1073/pnas.2207475119 |doi-access=free |pmc=9674242 |pmid=36343248 |access-date=24 November 2023 |hdl=10919/112639}}

There is evidence for a mass extinction during this period from early animals changing the environment,{{Cite journal |last1=Laflamme |first1=Marc |last2=Darroch |first2=Simon A. F. |last3=Tweedt |first3=Sarah M. |last4=Peterson |first4=Kevin J. |last5=Erwin |first5=Douglas H. |date=1 March 2013 |title=The end of the Ediacara biota: Extinction, biotic replacement, or Cheshire Cat? |url=https://www.sciencedirect.com/science/article/pii/S1342937X1200353X |journal=Gondwana Research |series=Geological processes in the Early Earth |volume=23 |issue=2 |pages=558–573 |doi=10.1016/j.gr.2012.11.004 |bibcode=2013GondR..23..558L |issn=1342-937X |access-date=24 November 2023}} dating to the same time as the transition between the White Sea and the Nama-type biotas.{{cite journal |last1=Darroch |first1=Simon A. F. |last2=Sperling |first2=Erik A. |last3=Boag |first3=Thomas H. |last4=Racicot |first4=Rachel A. |last5=Mason |first5=Sara J. |last6=Morgan |first6=Alex S. |last7=Tweedt |first7=Sarah |last8=Myrow |first8=Paul |last9=Johnston |first9=David T. |last10=Erwin |first10=Douglas H. |last11=Laflamme |first11=Marc |date=7 September 2015 |title=Biotic replacement and mass extinction of the Ediacara biota |journal=Proceedings of the Royal Society B: Biological Sciences |volume=282 |issue=1814 |pages=1–10 |doi=10.1098/rspb.2015.1003 |pmc=4571692 |pmid=26336166|bibcode=2015RSPSB.28251003D }}[https://www.sciencedaily.com/releases/2015/09/150902123456.htm Evidence that Earth's first mass extinction was caused by critters not catastrophe], ScienceDaily Alternatively, this mass extinction has also been theorised to have been the result of an anoxic event.

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.{{Cite journal | doi = 10.1029/1999RG900016 | last1 = Williams | first1 = George E. | date = 2000 | title = Geological constraints on the Precambrian history of Earth's rotation and the Moon's orbit | bibcode = 2000RvGeo..38...37W | journal = Reviews of Geophysics | volume = 38 | issue = 1| pages = 37–60 | citeseerx = 10.1.1.597.6421 | s2cid = 51948507 }}

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).[https://www.abc.net.au/science/articles/2014/09/01/4076259.htm Celebrating 50 years of ABC Science] Retrieved 18 March 2023.
• 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.

• {{Annotated link|List of fossil sites}} (with link directory)
• Avalon explosion
• End-Ediacaran extinction

{{Reflist|30em}}

{{Commons category|Ediacaran}}

• {{cite news

| url = http://news.bbc.co.uk/1/hi/sci/tech/3721481.stm

| title = 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

| publisher = BBC

| date = 2004-05-17

| location=London}}

• {{cite web

| title = Ediacaran Period

| work = GeoWhen Database

| url = http://www.stratigraphy.org/bak/geowhen/stages/Ediacaran.html

| access-date = 5 January 2006

| url-status = dead

| archive-url = https://web.archive.org/web/20191016220407/http://www.stratigraphy.org/bak/geowhen/stages/Ediacaran.html

| archive-date = 16 October 2019

}}

• [http://www.ucmp.berkeley.edu/vendian/vendian.html Introduction to the Vendian Period]
• [http://www.abc.net.au/catalyst/stories/s1785092.htm#transcript transcript] – Catalyst (Australian Broadcasting Corporation)
• [https://web.archive.org/web/20061113031119/http://members.rediff.com/mistakenpoint/ Mistaken Point Fauna: The Discovery]
• [http://www.abc.net.au/news/2013-08-03/sa-pastoral-property-nilpena-holds-animal-fossils/4862432 Earth's oldest animal ecosystem held in fossils at Nilpena Station in SA outback] ABC News, 5 August 2013. Accessed 6 August 2013.
• {{IMDb title|2380395|Australia: The Time Traveller's Guide (2012)}}
• [https://www.bbc.co.uk/programmes/b00lh2s3 In Our Time – Ediacara Biota], BBC Radio, 9 July 2009. Accessed 1 February 2025.

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Category:Geological periods

Category:Proterozoic geochronology