Ediacaran

The Ediacaran Period ( /iː.diːˈæk.ə.rən/ ee-dee-AK-ə-rən)[1] is a geological period that spans 94 million
years from the end of the Cryogenian Period 635 million years ago (Mya), to the beginning of the Cambrian
Period 541 Mya. It marks the end of the Proterozoic Eon, and the beginning of the Phanerozoic Eon. It is
named after the Ediacara Hills of South Australia.

The Ediacaran Period's 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.[2][3][4]
Although the period takes its name from the Ediacara Hills where geologist Reg Sprigg first discovered fossils
of the eponymous Ediacara biota in 1946,[5] the type section is located in the bed of the Enorama Creek[6]
within Brachina Gorge[7] in the Flinders Ranges of South Australia, at 31°19′53.8″S 138°38′0.1″E.

Contents
Ediacaran and Vendian
Upper and lower boundaries
Subdivisions
Absolute dating
Biota
Astronomical factors
Documentaries
See also
References
External links

Ediacaran and Vendian

The Ediacaran Period overlaps, but is shorter than the Vendian Period, 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.[8][9]

Paleontological substantiation of this boundary was worked out separately for the siliciclastic basin (base of the
Baltic Stage of the Eastern European Platform[10]) and for the carbonate basin (base of the Tommotian stage of
the Siberian Platform).[11] The lower boundary of the Vendian was suggested to be defined at the base of the
Varanger (Laplandian) tillites.[9][12]

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 Ediacaran Period
635–541 million years ago
abundant organic-walled microfossils, megascopic algae,
metazoan body fossils and ichnofossils.[9][13] PreꞒ Ꞓ O S D C P T J K PgN

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.[12]

Upper and lower boundaries

A map of the world as it appeared
The Ediacaran Period (c. 635–541 Mya) represents the time from during the mid-Ediacaran. (600 ma)
the end of global Marinoan glaciation to the first appearance
worldwide of somewhat complicated trace fossils (Treptichnus Mean atmospheric O 2 content
c. 8 vol %
pedum (Seilacher, 1955)).[2] over period duration
(40 % of modern
level)
c. 4500 ppm
Although the Ediacaran Period does contain soft-bodied fossils, Mean atmospheric CO 2 content (16 times pre-
over period duration
it is unusual in comparison to later periods because its beginning industrial level)

is not defined by a change in the fossil record. Rather, the Mean surface temperature over
c. 17 °C
(3 °C above
beginning is defined at the base of a chemically distinctive period duration
modern level)
carbonate layer that is referred to as a "cap carbonate", because it
caps glacial deposits. Events of the Ediacaran Period

This bed is characterized by an unusual depletion of 13 C that –P Cambrian

indicates a sudden climatic change at the end of the Marinoan ice -540 — Z
age. The lower boundary global boundary stratotype section –
(GSSP) of the Ediacaran is at the base of the cap carbonate -550 —
(Nuccaleena Formation), immediately above the Elatina –
diamictite in the Enorama Creek section, Brachina Gorge, -560 — Ediacaran
Biota
Flinders Ranges, South Australia. –N
-570 — e
o
The GSSP of the upper boundary of the Ediacaran is the lower –
p
boundary of the Cambrian on the SE coast of Newfoundland -580 — r
approved by the International Commission on Stratigraphy as a –o
preferred alternative to the base of the Tommotian Stage in Ediacaran
-590 — t
Siberia which was selected on the basis of the ichnofossil –e
Treptichnus pedum (Seilacher, 1955). In the history of r
-600 —
o
stratigraphy it was the first case of usage of bioturbations for the –z
System boundary definition. -610 — o
–i
Nevertheless, the definitions of the lower and upper boundaries -620 — c
of the Ediacaran on the basis of chemostratigraphy and –
ichnofossils are disputable.[12][14] -630 —
–
Cap carbonates generally have a restricted geographic -640 — Cryogenian
distribution (due to specific conditions of their precipitation) and
usually siliciclastic sediments laterally replace the cap carbonates Major Glacial period
Treptichnus pedum
LargeStratigraphic
negative scale of the ICS
in a rather short distance but cap carbonates do not occur above ←peak δ 13Ccarb
subdivisions and Precambrian/Cambrian
←excursion
~Baykonurian
every tillite elsewhere in the world. glaciation boundary.
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 l3 Ccarb
in the upper layer of the ocean.[12][15]

Furthermore, Oman presents in its stratigraphic record a large

negative carbon isotope excursion, within the Shuram[16]
Formation that is clearly away from any glacial evidence[17]
strongly questioning systematic association of negative δ l3 Ccarb
excursion and glacial events.[18] Also, the Shuram excursion is
prolonged and is estimated to last for ~9.0 Myrs.[19]

As to the Treptichnus pedum, a reference ichnofossil for the

lower boundary of the Cambrian, its usage for the stratigraphic The 'golden spike' (bronze disk in the
detection of this boundary is always risky, because of the lower section of the image) or 'type
occurrence of very similar trace fossils belonging to the section' of the Global Boundary Stratotype
Treptichnids group well below the level of T. pedum in Namibia, Section and Point (GSSP) for the base of
Spain and Newfoundland, and possibly, in the western United the Ediacaran System
States. The stratigraphic range of T. pedum overlaps the range of
the Ediacaran fossils in Namibia, and probably in Spain.[12][20]

Subdivisions
The Ediacaran period is not yet formally subdivided, but a proposed
scheme[21] 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
557 Ma with the earliest widespread Ediacaran biota fossils; two
proposed schemes differ on whether the lower strata should be The 'golden spike' marking the GSSP
divided into an Early and Middle Ediacaran or not, because it's 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 542 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) isochron dating from Namibia[22] and China.[23]

Applying this age to the base of the Ediacaran assumes that cap carbonates are laid down synchronously
around the world and that the correct cap carbonate layers have been selected in such diverse locales as
Australian and Namibia. This is controversial because an age of about 580 million years has been obtained for
glacial rocks in Tasmania which some scientists tentatively assign to those just beneath the Ediacaran rocks of
the Flinders Ranges.[24] The age of the top is the same as the widely recognised age for the base of the
Cambrian Period[25] 542± 0.3 Mya,[26] producing a misalignment, as the end of the Edicarian Period should
mark the start of the Cambrian Period.
Biota
The fossil record from the Ediacaran Period is sparse, as more easily fossilized hard-shelled animals had yet to
evolve. 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.

Some hard-shelled agglutinated foraminifera are known from latest Ediacaran sediments of western Siberia.[27]

Ediacara biota bear little resemblance to modern lifeforms, and their relationship even with the immediately
following lifeforms of the Cambrian explosion is rather difficult to interpret. More than 100 genera have been
described, and well known forms include Arkarua, Charnia, Dickinsonia, Ediacaria, Marywadea,
Cephalonega, Pteridinium, and Yorgia.

There is evidence for a mass extinction during this period from early animals changing the environment.[28]

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.[29]

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

The Time Traveller's Guide To Australia (2012, ABC Network Australia; Part 1 of 4).
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.
In our time - Ediacara Biota (http://www.bbc.co.uk/programmes/b00lh2s3), BBC, 9 July 2009

See also
List of fossil sites – A table of worldwide localities notable for the presence of fossils (with link
directory)
Avalon explosion
End-Ediacaran extinction

References
1. "Ediacaran" (https://www.dictionary.com/browse/Ediacaran). Dictionary.com Unabridged.
Random House.
2. A. Knoll, M. Walter, G. Narbonne, and N. Christie-Blick (2004) "The Ediacaran Period: A New
Addition to the Geologic Time Scale. (http://www.stratigraphy.org/bak/ediacaran/Knoll_et_al_20
04a.pdf)" Submitted on Behalf of the Terminal Proterozoic Subcommission of the International
Commission on Stratigraphy.
 3. Knoll, A. H.; Walter, MR; Narbonne, G. M; Christie-Blick, N (30 July 2004). "A new period for the
geologic time scale" (http://www.stratigraphy.org/bak/ediacaran/Knoll_et_al_2004b.pdf) (PDF).
Science. 305 (5684): 621–622. doi:10.1126/science.1098803 (https://doi.org/10.1126%2Fscien
ce.1098803). PMID 15286353 (https://pubmed.ncbi.nlm.nih.gov/15286353). S2CID 32763298
(https://api.semanticscholar.org/CorpusID:32763298).
4. Knoll, A. H.; Walter, M. R.; Narbonne, G. M. & Christie-Blick, N. (March 2006). "The Ediacaran
Period: A new addition to the geologic time scale" (https://web.archive.org/web/200702210849
15/http://geol.queensu.ca/people/narbonne/KnollWalterNarbonneChristieBlick_Lethaia_2006.p
df) (PDF). Lethaia. 39: 13–30. doi:10.1080/00241160500409223 (https://doi.org/10.1080%2F00
241160500409223). Archived from the original (http://geol.queensu.ca/people/narbonne/Knoll
WalterNarbonneChristieBlick_Lethaia_2006.pdf) (PDF) on 21 February 2007.
5. Sprigg, Reg. C. (1947). "Early Cambrian (?) jellyfishes from the Flinders Ranges, South
Australia" (https://www.biodiversitylibrary.org/page/41347851#page/234/mode/1up).
Transactions of the Royal Society of South Australia. 71 (2): 212–224.
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" (http://news.bbc.co.uk/1/hi/sci/tech/3721481.s
tm). London: BBC. 17 May 2004. Accessed 27 December 2010.
7. South Australian Museum Newsletter April 2005 (http://www.samuseum.sa.gov.au/page/defaul
t.asp?site=1&page=Newsletter&id=876&fragPage=1) Archived (https://web.archive.org/web/20
110217013850/http://www.samuseum.sa.gov.au/page/default.asp?site=1&page=Newsletter&id
=876&fragPage=1) 17 February 2011 at the Wayback Machine Accessed 9 August 2010.
8. 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.
9. Sokolov, B.S. (1997). "Essays on the Advent of the Vendian System." 153 pp. KMK Scientific
Press, Moscow. (in Russian)
10. Sokolov B. S. (1965) "Abstracts of All-Union Symposium on Paleontology of the Precambrian
and Early Cambrian." Nauka, Novosibirsk.
11. Rozanov, A.Y.; Missarzhevskij, V.V.; Volkova, N.A.; Voronova, L.G.; Krylov, I.N.; Keller, B.M.;
Korolyuk, I.K.; Lendzion, K.; Michniak, R.; Pykhova, N.G. & Sidorov, A.D. (1969). "The
Tommotian Stage and the problem of the lower boundary of the Cambrian". Trudy
Geologičeskogo Instituta AN SSSR. 206: 1–380.
12. M. A. Fedonkin; B. S. Sokolov; M. A. Semikhatov; N. M. Chumakov (2007). "Vendian versus
Ediacaran: priorities, contents, prospectives" (https://web.archive.org/web/20111004184527/htt
p://vendian.net76.net/Vendian_vs_Ediacaran.htm). Archived from the original (http://vendian.ne
t76.net/Vendian_vs_Ediacaran.htm) on 4 October 2011. In: "The Rise and Fall of the Vendian
(Ediacaran) Biota" (https://web.archive.org/web/20121122062305/http://www.geosci.monash.e
du.au/precsite/docs/workshop/moscow07/transaction.pdf) (PDF). Origin of the Modern
Biosphere. Transactions of the International Conference on the IGCP Project 493n Moscow:
GEOS. 20–31 August 2007. Archived from the original (http://www.geosci.monash.edu.au/prec
site/docs/workshop/moscow07/transaction.pdf) (PDF) on 22 November 2012. (82mb)
13. 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.
Bibcode:2008SGC....16..581K (https://ui.adsabs.harvard.edu/abs/2008SGC....16..581K).
doi:10.1134/S0869593808060014 (https://doi.org/10.1134%2FS0869593808060014).
S2CID 128966206 (https://api.semanticscholar.org/CorpusID:128966206).
14. 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. (http://www.stratigraphy.or
g/bak/ediacaran/Knoll_et_al_2004a.pdf)" Submitted on Behalf of the Terminal Proterozoic
Subcommission of the International Commission on Stratigraphy. pp. 32–34
15. Bristow, T. F.; Kennedy, M. J. (2008). "Carbon isotope excursions and the oxidant budget of the
Ediacaran atmosphere and ocean" (http://taylorandfrancis.metapress.com/index/PUNM6BQLN
W1BJMFN.pdf) (PDF). Geology. 36 (11): 863–866. Bibcode:2008Geo....36..863B (https://ui.ads
abs.harvard.edu/abs/2008Geo....36..863B). doi:10.1130/G24968A.1 (https://doi.org/10.1130%2
FG24968A.1). Retrieved 5 May 2007.
16. 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. Bibcode:2006PreR..146...68L (https://ui.adsabs.harvard.edu/abs/2006PreR..146...68L).
doi:10.1016/j.precamres.2006.01.007 (https://doi.org/10.1016%2Fj.precamres.2006.01.007).
17. 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" (https://archive.today/20130
105074949/http://www3.interscience.wiley.com/journal/118624047/abstract). Terra Nova. 18
(2): 147–153. Bibcode:2006TeNov..18..147L (https://ui.adsabs.harvard.edu/abs/2006TeNov..1
8..147L). doi:10.1111/j.1365-3121.2006.00674.x (https://doi.org/10.1111%2Fj.1365-3121.2006.
00674.x). Archived from the original (http://www3.interscience.wiley.com/journal/118624047/ab
stract) on 5 January 2013.
18. 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" (https://archive.today/20130105102240/http://www3.interscience.wiley.com/jour
nal/118629748/abstract). Basin Research. 18 (2): 205–220. Bibcode:2006BasR...18..205L (http
s://ui.adsabs.harvard.edu/abs/2006BasR...18..205L). doi:10.1111/j.1365-2117.2006.00292.x (ht
tps://doi.org/10.1111%2Fj.1365-2117.2006.00292.x). Archived from the original (http://www3.int
erscience.wiley.com/journal/118629748/abstract) on 5 January 2013.
19. 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. Bibcode:2017PreR..289...62G
(https://ui.adsabs.harvard.edu/abs/2017PreR..289...62G). doi:10.1016/j.precamres.2016.12.002
(https://doi.org/10.1016%2Fj.precamres.2016.12.002).
20. A. Ragozina, D. Dorjnamjaa, A. Krayushkin, E. Serezhnikova (2008). "Treptichnus pedum and
the Vendian-Cambrian boundary (http://vendian.net76.net/Treptichnus_pedum.htm)". 33 Intern.
Geol. Congr. August 6–14, 2008, Oslo, Norway. Abstracts. Section HPF 07 Rise and fall of the
Ediacaran (Vendian) biota. P. 183.
21. 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" (https://web.archive.org/web/20170820155807/http://ww
w.paleo.geos.vt.edu/Ediacaran/Xiao2016EdiacaranTimeScaleEpisodes.pdf) (PDF). Episodes.
39 (4): 540555. doi:10.18814/epiiugs/2016/v39i4/103886 (https://doi.org/10.18814%2Fepiiug
s%2F2016%2Fv39i4%2F103886). Archived from the original (http://www.paleo.geos.vt.edu/Edi
acaran/Xiao2016EdiacaranTimeScaleEpisodes.pdf) (PDF) on 20 August 2017. Retrieved
21 June 2017.
22. Hoffmann, K.H.; Condon, D.J.; Bowring, S.A.; Crowley, J.L. (1 September 2004). "U-Pb zircon
date from the Neoproterozoic Ghaub Formation, Namibia: Constraints on Marinoan glaciation".
Geology. 32 (9): 817–820. Bibcode:2004Geo....32..817H (https://ui.adsabs.harvard.edu/abs/20
04Geo....32..817H). doi:10.1130/G20519.1 (https://doi.org/10.1130%2FG20519.1).
23. Condon, D.; Zhu, M.; Bowring, S.; Wang, W.; Yang, A. & Jin, Y. (1 April 2005). "U-Pb Ages from
the Neoproterozoic Doushantuo Formation, China". Science. 308 (5718): 95–98.
Bibcode:2005Sci...308...95C (https://ui.adsabs.harvard.edu/abs/2005Sci...308...95C).
doi:10.1126/science.1107765 (https://doi.org/10.1126%2Fscience.1107765). PMID 15731406
(https://pubmed.ncbi.nlm.nih.gov/15731406). S2CID 11673032 (https://api.semanticscholar.org/
CorpusID:11673032).
24. Calver, C.R.; Black, Lance P.; Everard, John L.; Seymour, David B. (1 October 2004). "U-Pb
zircon age constraints on late Neoproterozoic glaciation in Tasmania". Geology. 32 (10): 893–
896. Bibcode:2004Geo....32..893C (https://ui.adsabs.harvard.edu/abs/2004Geo....32..893C).
doi:10.1130/G20713.1 (https://doi.org/10.1130%2FG20713.1).
25. Ogg, J. G. (2004). "Status of Divisions of the International Geologic Time Scale" (http://tayloran
dfrancis.metapress.com/index/PUNM6BQLNW1BJMFN.pdf) (PDF). Lethaia. 37 (2): 183–199.
doi:10.1080/00241160410006492 (https://doi.org/10.1080%2F00241160410006492).
Retrieved 5 May 2007.
26. Amthor, J. E.; Grotzinger, John P.; Schröder, Stefan; Bowring, Samuel A.; Ramezani, Jahandar;
Martin, Mark W.; Matter, Albert (2003). "Extinction of Cloudina and Namacalathus at the
Precambrian-Cambrian boundary in Oman". Geology. 31 (5): 431–434.
Bibcode:2003Geo....31..431A (https://ui.adsabs.harvard.edu/abs/2003Geo....31..431A).
doi:10.1130/0091-7613(2003)031<0431:EOCANA>2.0.CO;2 (https://doi.org/10.1130%2F0091-
7613%282003%29031%3C0431%3AEOCANA%3E2.0.CO%3B2).
27. Kontorovich, A. E.; Varlamov, A. I.; Grazhdankin, D. V.; Karlova, G. A.; Klets, A. G.; Kontorovich,
V. A.; Saraev, S. V.; Terleev, A. A.; Belyaev, S. Yu.; Varaksina, I. V.; Efimov, A. S. (1 December
2008). "A section of Vendian in the east of West Siberian Plate (based on data from the
Borehole Vostok 3)" (http://www.sciencedirect.com/science/article/pii/S106879710800206X).
Russian Geology and Geophysics. 49 (12): 932–939. doi:10.1016/j.rgg.2008.06.012 (https://do
i.org/10.1016%2Fj.rgg.2008.06.012). ISSN 1068-7971 (https://www.worldcat.org/issn/1068-797
1).
28. https://www.sciencedaily.com/releases/2015/09/150902123456.htm Science Daily
29. 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.
Bibcode:2000RvGeo..38...37W (https://ui.adsabs.harvard.edu/abs/2000RvGeo..38...37W).
doi:10.1029/1999RG900016 (https://doi.org/10.1029%2F1999RG900016).

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" (http://news.bbc.co.uk/1/hi/sci/tech/3721481.s
tm). London: BBC. 17 May 2004.
"Ediacaran Period" (http://www.stratigraphy.org/bak/geowhen/stages/Ediacaran.html).
GeoWhen Database. Retrieved 5 January 2006.
Introduction to the Vendian Period (http://www.ucmp.berkeley.edu/vendian/vendian.html)
Introduction to the Ediacaran Fauna (http://members.tripod.com/~Cambrian/IntrotoEdiacaran)
transcript (http://www.abc.net.au/catalyst/stories/s1785092.htm#transcript) – Catalyst
(Australian Broadcasting Corporation)
Mistaken Point Fauna: The Discovery (https://web.archive.org/web/20061113031119/http://me
mbers.rediff.com/mistakenpoint/)
Earth's oldest animal ecosystem held in fossils at Nilpena Station in SA outback (http://www.ab
c.net.au/news/2013-08-03/sa-pastoral-property-nilpena-holds-animal-fossils/4862432) ABC
News, 5 August 2013. Accessed 6 August 2013.

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