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Cryogenian

November 12, 2023

The Cryogenian (from Ancient Greek: κρύος, romanized: krýos, meaning "cold" and γένεσις, romanized: génesis, meaning "birth") is a geologic period that lasted from 720 to 635 million years ago.[6] It forms the second geologic period of the Neoproterozoic Era, preceded by the Tonian Period and followed by the Ediacaran.

Cryogenian
c. 720 – c. 635 Ma
A map of the world as it appeared at the start of the Cryogenian, c. 720 Ma
Chronology
Etymology
Name formalityFormal
Name ratified1990
Usage information
Celestial bodyEarth
Regional usageGlobal (ICS)
Time scale(s) usedICS Time Scale
Definition
Chronological unitPeriod
Stratigraphic unitSystem
Time span formalityFormal
Lower boundary definitionDefined chronometrically with an interim calibrated age of c. 720 Ma. GSSP is in progress.
Lower boundary definition candidatesThe first appearance of widespread glaciation.[4]
Lower boundary GSSP candidate section(s)To be determined
Upper boundary definition
  • Worldwide distinct cap carbonates.
  • Beginning of a distinctive pattern of secular changes in carbon isotopes.
Upper boundary GSSPEnorama Creek section, Flinders Ranges, South Australia
31°19′53″S 138°38′00″E / 31.3314°S 138.6334°E / -31.3314; 138.6334
Upper GSSP ratifiedMarch 2004[5]
Atmospheric and climatic data
Mean atmospheric O2 contentc. 12 vol %
(60 % of modern)
Mean atmospheric CO2 contentc. 1300 ppm
(5 times pre-industrial)
Mean surface temperaturec. 5 °C
(9 °C below modern)

The Cryogenian was a time of drastic biosphere changes. After the previous Boring Billion years of stability, at the beginning of Cryogenian the severe Sturtian glaciation began, freezing the entire Earth in a planetary state known as a Snowball Earth. After 70 million years it ended, but was quickly followed by the Marinoan glaciation, which was also a global event. These events are the subject of much scientific controversy specifically over whether these glaciations covered the entire planet or a band of open sea survived near the equator (termed "slushball Earth").

Ratification edit

The Cryogenian Period was ratified in 1990 by the International Commission on Stratigraphy.[7] In contrast to most other time periods, the beginning of the Cryogenian is not linked to a globally observable and documented event. Instead, the base of the period is defined by a fixed rock age, that was originally set at 850 million years,[8] but changed in 2015 to 720 million years.[6]

This could cause ambiguity because estimates of rock ages are variable and are subject to laboratory error. For instance, the time scale of the Cambrian Period is not reckoned by rock younger than a given age (538.8 million years), but by the appearance of the worldwide Treptichnus pedum diagnostic trace fossil assemblages. This means that rocks can be recognized as Cambrian in the field, without extensive lab testing.

Currently, there is no consensus on what global event is a suitable candidate to mark the start of the Cryogenian Period, but a global glaciation would be a likely candidate.[8]

Climate edit

The name of the geologic period refers to the very cold global climate of the Cryogenian.

Characteristic glacial deposits indicate that Earth suffered the most severe ice ages in its history during this period (Sturtian and Marinoan). According to Eyles and Young, "Late Proterozoic glaciogenic deposits are known from all the continents. They provide evidence of the most widespread and long-ranging glaciation on Earth." Several glacial periods are evident, interspersed with periods of relatively warm climate, with glaciers reaching sea level in low paleolatitudes.[9]

Glaciers extended and contracted in a series of rhythmic pulses, possibly reaching as far as the equator.[10]

 
Diamictite of the Elatina Formation in South Australia, formed during the Marinoan glaciation of the late Cryogenian

The Cryogenian is generally considered to be divisible into at least two major worldwide glaciations. The Sturtian glaciation persisted from 720 to 660 million years ago, and the Marinoan glaciation which ended approximately 635 Ma, at the end of the Cryogenian.[11] The deposits of glacial tillite also occur in places that were at low latitudes during the Cryogenian, a phenomenon which led to the hypothesis of deeply frozen planetary oceans called "Snowball Earth".[12] Between the Sturtian and Marinoan glaciations was a so-called "Cryogenian interglacial period" marked by relatively warm climate and anoxic oceans,[13] along with marine transgression.[14]

Paleogeography edit

Main article: Rodinia § Geodynamics

Before the start of the Cryogenian, around 750 Ma, the cratons that made up the supercontinent Rodinia started to rift apart. The superocean Mirovia began to close while the superocean Panthalassa began to form. The cratons (possibly) later assembled into another supercontinent called Pannotia, in the Ediacaran.

Eyles and Young state, "Most Neoproterozoic glacial deposits accumulated as glacially influenced marine strata along rifted continental margins or interiors." Worldwide deposition of dolomite might have reduced atmospheric carbon dioxide. The break up along the margins of Laurentia at about 750 Ma occurs at about the same time as the deposition of the Rapitan Group in North America, contemporaneously with the Sturtian in Australia. A similar period of rifting at about 650 Ma occurred with the deposition of the Ice Brook Formation in North America, contemporaneously with the Marinoan in Australia.[9] The Sturtian and Marinoan are local divisions within the Adelaide Rift Complex.

Cryogenian biota and fossils edit

Between the Sturtian and Marinoan glaciations, global biodiversity was very low.[13]

Fossils of testate amoeba (or Arcellinida) first appear during the Cryogenian Period.[15] Since 2009, some researchers have argued that during the Cryogenian Period, potentially the oldest known fossils of sponges, and therefore animals, were formed.[16][17][18] However, it is unclear whether these fossils actually belong to sponges, though the authors do not rule out the possibility of such fossils to represent proto-sponges or complex microbial precursors to sponge-grade organisms.[19] The issue of whether or not biology was impacted by this event has not been settled, for example Porter (2000) suggests that new groups of life evolved during this period, including the red algae and green algae, stramenopiles, ciliates, dinoflagellates, and testate amoeba.[20]

The end of the period also saw the origin of heterotrophic plankton, which would feed on unicellular algae and prokaryotes, ending the bacterial dominance of the oceans.[21]

See also edit

References edit

  1. ^ a b Arnaud, Emmanuelle; Halverson, Galen P.; Shields-Zhou, Graham Anthony (30 November 2011). "Chapter 1 The geological record of Neoproterozoic ice ages". Memoirs. Geological Society of London. 36 (1): 1–16. doi:10.1144/M36.1.
  2. ^ a b Hoffman, Paul F.; Abbot, Dorian S.; Ashkenazy, Yosef; Benn, Douglas I.; Brocks, Jochen J.; Cohen, Phoebe A.; Cox, Grant M.; Creveling, Jessica R.; Donnadieu, Yannick; Erwin, Douglas H.; Fairchild, Ian J.; Ferreira, David; Goodman, Jason C.; Halverson, Galen P.; Jansen, Malte F. (2017-11-03). "Snowball Earth climate dynamics and Cryogenian geology-geobiology". Science Advances. 3 (11): e1600983. doi:10.1126/sciadv.1600983. ISSN 2375-2548. PMC 5677351. PMID 29134193.
  3. ^ Brocks, Jochen J. (2018-09-28). Lyons, Timothy W.; Droser, Mary L.; Lau, Kimberly V.; Porter, Susannah M. (eds.). "The transition from a cyanobacterial to algal world and the emergence of animals". Emerging Topics in Life Sciences. 2 (2): 181–190. doi:10.1042/ETLS20180039. ISSN 2397-8554.
  4. ^ Shields-Zhou, Graham A.; Porter, Susannah; Halverson, Galen P. (2016). "A new rock-based definition for the Cryogenian Period (circa 720 – 635 Ma)" (PDF). Episodes. 39 (1): 3–8. doi:10.18814/epiiugs/2016/v39i1/89231. ISSN 0705-3797.
  5. ^ Knoll, Andrew H.; Walter, Malcolm R.; Narbonne, Guy M.; Christie-Black, Nicholas (3 March 2006). "The Ediacaran Period: a new addition to the geologic time scale" (PDF). Lethaia. 39: 13–30. doi:10.1080/00241160500409223. Retrieved 6 December 2020.
  6. ^ a b . International Commission on Stratigraphy. Archived from the original on 13 January 2017. Retrieved 14 February 2017.
  7. ^ Plumb, Kenneth A. (1991). "New Precambrian time scale" (PDF). Episodes. 2. 14 (2): 134–140. doi:10.18814/epiiugs/1991/v14i2/005. Retrieved 7 September 2013.
  8. ^ a b "GSSP Table - Precambrian". Geologic Timescale Foundation. Retrieved 7 September 2013.
  9. ^ a b Eyles, Nicholas; Young, Grant (1994). Deynoux, M.; Miller, J.M.G.; Domack, E.W.; Eyles, N.; Fairchild, I.J.; Young, G.M. (eds.). Geodynamic controls on glaciation in Earth history, in Earth's Glacial Record. Cambridge: Cambridge University Press. pp. 5–10. ISBN 0521548039.
  10. ^ Dave Lawrence (2003). "Microfossil lineages support sloshy snowball Earth". Geotimes.
  11. ^ Shields, G. A. (2008). "Palaeoclimate: Marinoan meltdown". Nature Geoscience. 1 (6): 351–353. Bibcode:2008NatGe...1..351S. doi:10.1038/ngeo214.
  12. ^ Hoffman, P.F. 2001. Snowball Earth theory
  13. ^ a b Xu, Lingang; Frank, Anja B.; Lehmann, Bernd; Zhu, Jianming; Mao, Jingwen; Ju, Yongze; Frei, Robert (21 October 2019). "Subtle Cr isotope signals track the variably anoxic Cryogenian interglacial period with voluminous manganese accumulation and decrease in biodiversity". Scientific Reports. 9 (1): 1–8. doi:10.1038/s41598-019-51495-0. ISSN 2045-2322. PMC 6803686. PMID 31636318. Retrieved 11 September 2023.
  14. ^ Freitas, B.T.; Rudnitzki, I.D.; Morais, L.; Campos, M.D.R.; Almeida, R.P.; Warren, L.V.; Boggiani, P.C.; Caetano-Filho, S.; Bedoya-Rueda, C.; Babinski, M.; Fairchild, T.R.; Trindade, R.I.F. (30 August 2021). "Cryogenian glaciostatic and eustatic fluctuations and massive Marinoan-related deposition of Fe and Mn in the Urucum District, Brazil". Geology. 49 (12): 1478–1483. doi:10.1130/G49134.1. ISSN 0091-7613. Retrieved 11 September 2023.
  15. ^ Porter, S.A. & Knoll, A.H. (2000). "Testate amoeba in the Neoproterozoic Era: evidence from vase-shaped microfossils in the Chuar Group, Grand Canyon". Paleobiology. 26 (3): 360–385. doi:10.1666/0094-8373(2000)026<0360:TAITNE>2.0.CO;2. ISSN 0094-8373. S2CID 54636062.
  16. ^ Love; Grosjean, Emmanuelle; Stalvies, Charlotte; Fike, David A.; Grotzinger, John P.; Bradley, Alexander S.; Kelly, Amy E.; Bhatia, Maya; Meredith, William; et al. (2009). (PDF). Nature. 457 (7230): 718–721. Bibcode:2009Natur.457..718L. doi:10.1038/nature07673. PMID 19194449. S2CID 4314662. Archived from the original (PDF) on 2018-05-08. Retrieved 2009-04-15.
  17. ^ Maloof, Adam C.; Rose, Catherine V.; Beach, Robert; Samuels, Bradley M.; Calmet, Claire C.; Erwin, Douglas H.; Poirier, Gerald R.; Yao, Nan; Simons, Frederik J. (17 August 2010). "Possible animal-body fossils in pre-Marinoan limestones from South Australia". Nature Geoscience. 3 (9): 653–659. Bibcode:2010NatGe...3..653M. doi:10.1038/ngeo934.
  18. ^ "Discovery of possible earliest animal life pushes back fossil record". 2010-08-17.
  19. ^ Wallace, M.W.; Hood, A.v.S.; Woon, E.M.S.; Hoffman, K.-H.; Reed, C.P. (2014). "Enigmatic chambered structures in Cryogenian reefs: The oldest sponge-grade organisms?". Precambrian Research. 255: 653–659. doi:10.1016/j.precamres.2014.09.020. hdl:11343/52679.
  20. ^ "Palaeos Proterozoic: Neoproterozoic: Cryogenian".
  21. ^ Fossil fats reveal how complex life kicked off after Snowball Earth phase

Further reading edit

  • . GeoWhen Database. Archived from the original on December 2, 2005. Retrieved January 5, 2006.
  • James G. Ogg (2004). "Status on Divisions of the International Geologic Time Scale". Lethaia. 37 (2): 183–199. doi:10.1080/00241160410006492.
  • Brain, C. K.; Prave, A. R.; Hoffmann, K. H.; Fallick, A. E.; Herd, D. A.; Sturrock, C.; Young, I.; Condon, D. J.; Allison, S. G. (2012). "The first animals: ca. 760-million-year-old sponge-like fossils from Namibia" (PDF). South African Journal of Science. 108: 1–8. doi:10.4102/sajs.v108i1/2.658.
  • Hoffman, Paul F.; Abbot, Dorian S.; et al. (November 8, 2017). "Snowball Earth climate dynamics and Cryogenian geology-geobiology". Science Advances. American Association for the Advancement of Science. 3 (11): e1600983. Bibcode:2017SciA....3E0983H. doi:10.1126/sciadv.1600983. PMC 5677351. PMID 29134193. S2CID 1465316.

External links edit

  • The Time Travellers Guide to Australia (2012) at IMDb
  • Miracle Planet : Snowball Earth on YouTube (2010s) BBC/CBC/NHK

November 12, 2023
cryogenian, from, ancient, greek, κρύος, romanized, krýos, meaning, cold, γένεσις, romanized, génesis, meaning, birth, geologic, period, that, lasted, from, million, years, forms, second, geologic, period, neoproterozoic, preceded, tonian, period, followed, ed. The Cryogenian from Ancient Greek kryos romanized kryos meaning cold and genesis romanized genesis meaning birth is a geologic period that lasted from 720 to 635 million years ago 6 It forms the second geologic period of the Neoproterozoic Era preceded by the Tonian Period and followed by the Ediacaran Cryogenianc 720 c 635 Ma Pha Proterozoic Archean Had A map of the world as it appeared at the start of the Cryogenian c 720 MaChronology 720 710 700 690 680 670 660 650 640 630 NeoproterozoicTonianCryogenianEdiacaran Marinoan glaciation 1 2 Transition from cyanobacterial to algal dominated world 3 Sturtian 1 2 Major Glacial periodEvents of the Cryogenian periodAxis Scale Millions of Years Ago Ma EtymologyName formalityFormalName ratified1990Usage informationCelestial bodyEarthRegional usageGlobal ICS Time scale s usedICS Time ScaleDefinitionChronological unitPeriodStratigraphic unitSystemTime span formalityFormalLower boundary definitionDefined chronometrically with an interim calibrated age of c 720 Ma GSSP is in progress Lower boundary definition candidatesThe first appearance of widespread glaciation 4 Lower boundary GSSP candidate section s To be determinedUpper boundary definitionWorldwide distinct cap carbonates Beginning of a distinctive pattern of secular changes in carbon isotopes Upper boundary GSSPEnorama Creek section Flinders Ranges South Australia31 19 53 S 138 38 00 E 31 3314 S 138 6334 E 31 3314 138 6334Upper GSSP ratifiedMarch 2004 5 Atmospheric and climatic dataMean atmospheric O2 contentc 12 vol 60 of modern Mean atmospheric CO2 contentc 1300 ppm 5 times pre industrial Mean surface temperaturec 5 C 9 C below modern The Cryogenian was a time of drastic biosphere changes After the previous Boring Billion years of stability at the beginning of Cryogenian the severe Sturtian glaciation began freezing the entire Earth in a planetary state known as a Snowball Earth After 70 million years it ended but was quickly followed by the Marinoan glaciation which was also a global event These events are the subject of much scientific controversy specifically over whether these glaciations covered the entire planet or a band of open sea survived near the equator termed slushball Earth Contents 1 Ratification 2 Climate 3 Paleogeography 4 Cryogenian biota and fossils 5 See also 6 References 7 Further reading 8 External linksRatification editThe Cryogenian Period was ratified in 1990 by the International Commission on Stratigraphy 7 In contrast to most other time periods the beginning of the Cryogenian is not linked to a globally observable and documented event Instead the base of the period is defined by a fixed rock age that was originally set at 850 million years 8 but changed in 2015 to 720 million years 6 This could cause ambiguity because estimates of rock ages are variable and are subject to laboratory error For instance the time scale of the Cambrian Period is not reckoned by rock younger than a given age 538 8 million years but by the appearance of the worldwide Treptichnus pedum diagnostic trace fossil assemblages This means that rocks can be recognized as Cambrian in the field without extensive lab testing Currently there is no consensus on what global event is a suitable candidate to mark the start of the Cryogenian Period but a global glaciation would be a likely candidate 8 Climate editThe name of the geologic period refers to the very cold global climate of the Cryogenian Characteristic glacial deposits indicate that Earth suffered the most severe ice ages in its history during this period Sturtian and Marinoan According to Eyles and Young Late Proterozoic glaciogenic deposits are known from all the continents They provide evidence of the most widespread and long ranging glaciation on Earth Several glacial periods are evident interspersed with periods of relatively warm climate with glaciers reaching sea level in low paleolatitudes 9 Glaciers extended and contracted in a series of rhythmic pulses possibly reaching as far as the equator 10 nbsp Diamictite of the Elatina Formation in South Australia formed during the Marinoan glaciation of the late CryogenianThe Cryogenian is generally considered to be divisible into at least two major worldwide glaciations The Sturtian glaciation persisted from 720 to 660 million years ago and the Marinoan glaciation which ended approximately 635 Ma at the end of the Cryogenian 11 The deposits of glacial tillite also occur in places that were at low latitudes during the Cryogenian a phenomenon which led to the hypothesis of deeply frozen planetary oceans called Snowball Earth 12 Between the Sturtian and Marinoan glaciations was a so called Cryogenian interglacial period marked by relatively warm climate and anoxic oceans 13 along with marine transgression 14 Paleogeography editMain article Rodinia Geodynamics Before the start of the Cryogenian around 750 Ma the cratons that made up the supercontinent Rodinia started to rift apart The superocean Mirovia began to close while the superocean Panthalassa began to form The cratons possibly later assembled into another supercontinent called Pannotia in the Ediacaran Eyles and Young state Most Neoproterozoic glacial deposits accumulated as glacially influenced marine strata along rifted continental margins or interiors Worldwide deposition of dolomite might have reduced atmospheric carbon dioxide The break up along the margins of Laurentia at about 750 Ma occurs at about the same time as the deposition of the Rapitan Group in North America contemporaneously with the Sturtian in Australia A similar period of rifting at about 650 Ma occurred with the deposition of the Ice Brook Formation in North America contemporaneously with the Marinoan in Australia 9 The Sturtian and Marinoan are local divisions within the Adelaide Rift Complex Cryogenian biota and fossils editBetween the Sturtian and Marinoan glaciations global biodiversity was very low 13 Fossils of testate amoeba or Arcellinida first appear during the Cryogenian Period 15 Since 2009 some researchers have argued that during the Cryogenian Period potentially the oldest known fossils of sponges and therefore animals were formed 16 17 18 However it is unclear whether these fossils actually belong to sponges though the authors do not rule out the possibility of such fossils to represent proto sponges or complex microbial precursors to sponge grade organisms 19 The issue of whether or not biology was impacted by this event has not been settled for example Porter 2000 suggests that new groups of life evolved during this period including the red algae and green algae stramenopiles ciliates dinoflagellates and testate amoeba 20 The end of the period also saw the origin of heterotrophic plankton which would feed on unicellular algae and prokaryotes ending the bacterial dominance of the oceans 21 See also editTimeline of glaciation Chronology of the major ice ages of the EarthReferences edit a b Arnaud Emmanuelle Halverson Galen P Shields Zhou Graham Anthony 30 November 2011 Chapter 1 The geological record of Neoproterozoic ice ages Memoirs Geological Society of London 36 1 1 16 doi 10 1144 M36 1 a b Hoffman Paul F Abbot Dorian S Ashkenazy Yosef Benn Douglas I Brocks Jochen J Cohen Phoebe A Cox Grant M Creveling Jessica R Donnadieu Yannick Erwin Douglas H Fairchild Ian J Ferreira David Goodman Jason C Halverson Galen P Jansen Malte F 2017 11 03 Snowball Earth climate dynamics and Cryogenian geology geobiology Science Advances 3 11 e1600983 doi 10 1126 sciadv 1600983 ISSN 2375 2548 PMC 5677351 PMID 29134193 Brocks Jochen J 2018 09 28 Lyons Timothy W Droser Mary L Lau Kimberly V Porter Susannah M eds The transition from a cyanobacterial to algal world and the emergence of animals Emerging Topics in Life Sciences 2 2 181 190 doi 10 1042 ETLS20180039 ISSN 2397 8554 Shields Zhou Graham A Porter Susannah Halverson Galen P 2016 A new rock based definition for the Cryogenian Period circa 720 635 Ma PDF Episodes 39 1 3 8 doi 10 18814 epiiugs 2016 v39i1 89231 ISSN 0705 3797 Knoll Andrew H Walter Malcolm R Narbonne Guy M Christie Black Nicholas 3 March 2006 The Ediacaran Period a new addition to the geologic time scale PDF Lethaia 39 13 30 doi 10 1080 00241160500409223 Retrieved 6 December 2020 a b Chart International Commission on Stratigraphy Archived from the original on 13 January 2017 Retrieved 14 February 2017 Plumb Kenneth A 1991 New Precambrian time scale PDF Episodes 2 14 2 134 140 doi 10 18814 epiiugs 1991 v14i2 005 Retrieved 7 September 2013 a b GSSP Table Precambrian Geologic Timescale Foundation Retrieved 7 September 2013 a b Eyles Nicholas Young Grant 1994 Deynoux M Miller J M G Domack E W Eyles N Fairchild I J Young G M eds Geodynamic controls on glaciation in Earth history in Earth s Glacial Record Cambridge Cambridge University Press pp 5 10 ISBN 0521548039 Dave Lawrence 2003 Microfossil lineages support sloshy snowball Earth Geotimes Shields G A 2008 Palaeoclimate Marinoan meltdown Nature Geoscience 1 6 351 353 Bibcode 2008NatGe 1 351S doi 10 1038 ngeo214 Hoffman P F 2001 Snowball Earth theory a b Xu Lingang Frank Anja B Lehmann Bernd Zhu Jianming Mao Jingwen Ju Yongze Frei Robert 21 October 2019 Subtle Cr isotope signals track the variably anoxic Cryogenian interglacial period with voluminous manganese accumulation and decrease in biodiversity Scientific Reports 9 1 1 8 doi 10 1038 s41598 019 51495 0 ISSN 2045 2322 PMC 6803686 PMID 31636318 Retrieved 11 September 2023 Freitas B T Rudnitzki I D Morais L Campos M D R Almeida R P Warren L V Boggiani P C Caetano Filho S Bedoya Rueda C Babinski M Fairchild T R Trindade R I F 30 August 2021 Cryogenian glaciostatic and eustatic fluctuations and massive Marinoan related deposition of Fe and Mn in the Urucum District Brazil Geology 49 12 1478 1483 doi 10 1130 G49134 1 ISSN 0091 7613 Retrieved 11 September 2023 Porter S A amp Knoll A H 2000 Testate amoeba in the Neoproterozoic Era evidence from vase shaped microfossils in the Chuar Group Grand Canyon Paleobiology 26 3 360 385 doi 10 1666 0094 8373 2000 026 lt 0360 TAITNE gt 2 0 CO 2 ISSN 0094 8373 S2CID 54636062 Love Grosjean Emmanuelle Stalvies Charlotte Fike David A Grotzinger John P Bradley Alexander S Kelly Amy E Bhatia Maya Meredith William et al 2009 Fossil steroids record the appearance of Demospongiae during the Cryogenian period PDF Nature 457 7230 718 721 Bibcode 2009Natur 457 718L doi 10 1038 nature07673 PMID 19194449 S2CID 4314662 Archived from the original PDF on 2018 05 08 Retrieved 2009 04 15 Maloof Adam C Rose Catherine V Beach Robert Samuels Bradley M Calmet Claire C Erwin Douglas H Poirier Gerald R Yao Nan Simons Frederik J 17 August 2010 Possible animal body fossils in pre Marinoan limestones from South Australia Nature Geoscience 3 9 653 659 Bibcode 2010NatGe 3 653M doi 10 1038 ngeo934 Discovery of possible earliest animal life pushes back fossil record 2010 08 17 Wallace M W Hood A v S Woon E M S Hoffman K H Reed C P 2014 Enigmatic chambered structures in Cryogenian reefs The oldest sponge grade organisms Precambrian Research 255 653 659 doi 10 1016 j precamres 2014 09 020 hdl 11343 52679 Palaeos Proterozoic Neoproterozoic Cryogenian Fossil fats reveal how complex life kicked off after Snowball Earth phaseFurther reading edit Cryogenian Period GeoWhen Database Archived from the original on December 2 2005 Retrieved January 5 2006 James G Ogg 2004 Status on Divisions of the International Geologic Time Scale Lethaia 37 2 183 199 doi 10 1080 00241160410006492 Brain C K Prave A R Hoffmann K H Fallick A E Herd D A Sturrock C Young I Condon D J Allison S G 2012 The first animals ca 760 million year old sponge like fossils from Namibia PDF South African Journal of Science 108 1 8 doi 10 4102 sajs v108i1 2 658 Hoffman Paul F Abbot Dorian S et al November 8 2017 Snowball Earth climate dynamics and Cryogenian geology geobiology Science Advances American Association for the Advancement of Science 3 11 e1600983 Bibcode 2017SciA 3E0983H doi 10 1126 sciadv 1600983 PMC 5677351 PMID 29134193 S2CID 1465316 External links editThe Time Travellers Guide to Australia 2012 at IMDb Miracle Planet Snowball Earth on YouTube 2010s BBC CBC NHK Portals nbsp Geology nbsp Paleontology Retrieved from https en wikipedia org w index php title Cryogenian amp oldid 1183430317, wikipedia, wiki, book, books, library,

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