Siderian

Siderian
A Siderian banded iron formation in Dales Gorge, Western Australia
Artist's impression of the Earth during the Huronian glaciation, starting from the mid-Siderian
Chronology
−2520 —
−2500 —
−2480 —
−2460 —
−2440 —
−2420 —
−2400 —
−2380 —
−2360 —
−2340 —
−2320 —
−2300 —
−2280 —
Paleoproterozoic
 
 
 
 
Beginning of the Great Oxidation Event
Breakup of the supercontinent Kenorland[2]
Events of the Siderian Period
Vertical axis scale: Millions of years ago
Proposed redefinition(s)2630–2420 Ma
Gradstein et al., 2012
Proposed containerNeoarchean
Gradstein et al., 2012
Etymology
Name formalityFormal
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
Lower GSSA ratified1990[3]
Upper boundary definitionDefined Chronometrically
Upper GSSA ratified1990[3]
Atmospheric and climatic data
Mean atmospheric O2 contentc. 0.014007 vol %
(0% of modern)
Mean atmospheric CO2 contentc. 11000 ppm
(39 times pre-industrial)

The Siderian ( /sˈdɪəri.ən, sɪ-/) is the first geologic period in the Paleoproterozoic Era and Proterozoic Eon. It lasted from 2500 to 2300 million years ago (Ma), spanning a time of 200 million years, and is followed by the Rhyacian Period. Instead of being based on stratigraphy, these dates are defined chronometrically.

The name Siderian is derived from the Greek word sideros, meaning "iron", and refers to the banded iron formations formed during this period. The term was proposed by the Subcommission on Precambrian Stratigraphy as a subdivision of the Proterozoic Eon, and was ratified by the International Union of Geological Sciences in 1990.[3][4] Since the Siderian is well-defined by the lower edge of iron-deposition layers and the initial appearance of glacial deposits, alternate names have been suggested to mark the upper half of the period stratigraphically. The term Oxygenian was suggested in 2012 due to the change in Earth’s atmosphere during this time,[5] while the name Skourian was proposed in 2021 as a rock-based alternative.[6] As of December 2024, the Siderian is the earliest internationally recognized period on the geological timescale.[7]

The deposition of banded iron formations (BIFs) peaked early in this period. These iron-rich formations were formed as anaerobic cyanobacteria produced waste oxygen that combined with iron, forming magnetite (Fe3O4, an iron oxide). This process removed iron from the Earth's oceans, presumably turning greenish seas clear. Eventually, with no remaining iron in the oceans to serve as an oxygen sink, the process allowed the buildup of an oxygen-rich atmosphere. This second, follow-on event is known as the oxygen catastrophe, which some geologists believe triggered the Huronian glaciation.[8][9]

Paleogeography

Paleotectonics and deposition

Tectonic activity mainly revolved around the growth of continental plates during the early Siderian. Many cratons at the time, including the Gawler, Superior, and Pilbara cratons, experienced volcanic activity through a global plume breakout, which occurred from 2500 to 2450 Ma. During that time, depositions at banded iron formations began occurring at the Kaapvaal and Pilbara cratons.[10] Additionally, volcanic and sedimentary rocks have begun to deposit into the Transvaal Basin at 2400 Ma, lasting until 2000 Ma in the Orosirian Period.[11]

Some depositional activity in what would become present-day Australia involved a selection of supersequences, consisting of a diverse set of densely packed sediments. The Brockman Supersequence, lasting from 2500 to 2449 Ma, has been shown to at least consist of mudrock and sediments from BIFs, which have been deposited during rising sea levels and times of volcanic activity.[12] Additionally, there have been traces of sulfur isotopes found in this sequence's Brockman Iron Formation, indicating a rise in the atmosphere's oxygen at the time.[13] The Woongarra Supersequence followed, consisting of depositions mainly from rhyolite, but with layers of dolerite and basalt present beforehand, occurring 2449 Ma.[14] It was then capped by the Turee Creek Supersequence, which presents itself with a layer of rhyodacite-basalt and sandstone sequences, and lasted from 2449 to 2410 Ma before a stratigraphic hiatus occurred.[12]

On the North American plate, sediments began to pack themselves and form the Huronian and Snowy Pass supergroups. Sandstone in the Huronian Supergroup was depositied in diverse compositions between 2450 and 2219 Ma, with some layers taking arkosic, felspathic, and quartzose structures.[15][16] While major depositions involved conglomerates of siltstone, limestone, and granite,[17] there were trace amounts of gold, uranium, and aluminium present as well.[18][19] In the Wyoming Craton, the Snowy Pass Supergroup holds signs of quartzite deposited throughout its layers, accompanied by sedimentary structures of marble, phyllite, and pebble conglomerates.[20] Additionally, there have been deposits of rhythmite and dropstone in northern Canada's Hurwitz Group between 2450 and 2110 Ma.[21] The extent of these laurentian depositions ranges from glacial origins and ice sheets to rivers and shallow marine conditions.[17][22]

Magmatism

Magma in the form of dike swarms has penetrated the surface of multiple cratons during the Siderian, taking place in some of the major continental plates such as those spanning North America, South Africa, and Australia. About 2470 Ma, the tholeiitic and komatiitic Mistassini dike swarm penetrated the Superior Craton.[23] With a surface area of at least 100,000 square kilometers, it can be classified as a large igneous province (LIP).[24] It is followed by the Matachewan dike swarm, an LIP occurring from about 2470 to 2450 Ma, and spanning a surface area of at least 300,000 square kilometers. The Mistassini and Matachewan swarms can be genetically associated with each other, as the Matachewan swarm has intruded into the Superior Craton in the area between Lake Superior and James Bay.[25] The Scourie dike swarm penetrated the Lewisian Gneiss Complex from about 2418 to 2375 Ma,[26] while the Widgiemooltha dike swarm intruded into the Yilgarn Craton at around 2410 Ma. The Widgiemooltha swarm occurred in close proximity to the Sebanga Poort dike's intrusion into the Zimbabwe Craton, which occurred about 2408 Ma.[27]

Breakup of Kenorland

Tectonic rifting began separating the supercontinent Kenorland at around 2450 Ma, with the breakup mainly occuring in Laurentia.[2] As a result, the Hurwitz Group in northern Canada experienced continential stretching and depression, resulting in the depositions of the Noomut, Padlei, and Kinga Formations, along with the creation of the Hurwitz Basin.[28] Additionally, low sulfidation deposits holding copper and nickel began to form in the Nena and Kalahari cratons,[2] while zircons formed within the Deep Lake Group in what is now the Sierra Madre Range.[29][30] Despite the intrusions contributing to the rifting, Kenorland experienced little continential movement, and there have been no signs of ocean development as a result. However, sedimentation from shallow waters began to occupy the Strel'na Group, in what is now the Kola Peninsula.[31][32]

Climate

Great Oxidation Event

Since the beginning of the Siderian, there has been an irreversible rise of oxygen in the Earth’s atmosphere, which has come to be known as the Great Oxidation Event. The partial pressure of oxygen in the air (pO2) has been shown to have increased to at least 104 times its original level, rising from 2 × 10−6 bar to at least 2 × 10−3 bar between 2410 and 2320 Ma.[33][34] As a result, the rapid change came at the expense of greenhouse gases such as carbon dioxide and methane, indirectly leading to a series of ice ages known as the Huronian glaciation.[35]

The levels of carbonates and organic carbon have been relatively stagnant. The abundance of carbon-13 isotopes (δ13C), found within dolomites and formations in the Mount Bruce, Transvaal, and Huronian supergroups, has maintained a steady level of 0‰ in carbonates, while organic carbon created through the activity and burial of cyanobacteria remained stationary at approximately −28‰.[36]: 3819–3820 [37] Although this may present itself as a sign of inactivity during this period, it suggests that there has been multiple sources causing an equal force of sinks and rises in the levels of oxygen.[38] This includes the influx and settlement of carbon dioxide from volcanic activity which stems from tectonic processes,[39] along with the delivery of phosphate to oceans through cycles of chemical weathering.[40]

As a consequence of the excess oxygen, a shift began to occur in the level and activity of greenhouse gases. The carbon dioxide in the atmosphere maintained equilibrium at a partial pressure of 1.1 × 10−2 bar, due to the oxidation of methane in the air, silicate weathering on the surface, and emissions from volcanic activity.[9][41] However, this process depleted the amounts of methane by a significant amount, dropping from 300 to 4 ppmv.[42] Despite the balance in carbon dioxide, the significant change in methane caused Earth to undergo a snowball event, dropping the average global temperatures below 0°C.[9]: 11134 

Huronian glaciation

Due to the loss of global temperature, the Earth entered the Huronian glaciation, which lasted from about 2450 to 2200 Ma.[43] While this event has been divided into four separate glaciations, only the first three occur in the Siderian Period, serving as a reaction to the oxidizing environment.[44] Traces of the glaciation have been found in the diamictites and sequences of six cratons,[45] including the Wyoming, Kaapvaal, and Karelia-Kola cratons.[44]

The oldest glaciation correlates to quartz located in the Campbell Lake and Headquarters formations,[46] along with glacial deposits in the Polisarka Formation.[47] It lasted from about 2440 to 2420 Ma,[44] and is generally referred to after the diamictites found in the Duitschland Formation.[48] The second glaciation, known as the Makganyene glaciation after its eponymous formation, is marked by cap carbonate sequences found above the Bruce and Vagner formations,[49] occuring from about 2380 to 2360 Ma.[44] The youngest of the three glaciations occurs from about 2340 to 2310 Ma near the end of the Siderian,[44] represented on the Gowganda Formation in the Huronian Supergroup, and referred to after the Rietfontein diamictite located in South Africa.[50]

Life

By the beginning of the Great Oxidation Event, cyanobacteria have developed intercelluar communication through molecular exchange, and have begun to differentiate from each other. Strands such as those in the Pseudanabaena genus began chaining themselves in a filamentous structure,[51] and Giardia, one of the earliest eukaryotes, began to appear at around 2309 Ma.[52][53] Traces of these bacteria have made marks in a few deposition sites. Microfossils in Australia's Turee Creek Group are embedded in black chert, which dates back to 2450 Ma.[54] In China, stromatolites have been spotted in the Dashiling and Qingshicun formations of the Hutuo Group, existing for the duration of the Siderian Period.[55] Additionally, findings in the Fennoscandian Shield show that the taxonomy of stromatolites began to diversify at around 2330 Ma.[56]

Marine geochemistry

In correspondence with the Great Oxidation Event, there has been a shift in the concentration levels of the Earth's oceans. At around 2300 Ma, the values of the relative abundance of iron-56 isotopes56Fe) increased in oceans by up to 3‰, compared to those in the Archean Era. This has been correlated with the oceanic deep stratification and an increase in sulfide precipitation, compared to iron oxide precipitation, as zero or slightly positive δ56Fe values are characteristic of seawater under an oxygenated atmosphere. Today, the δ56Fe values are no longer below –0.5‰, whereas in the Archean, they could still fall to –3.5‰.[57][58]

The increase in δ56Fe values has caused a reduced influence on iron cycling in open seawater. This has been interpreted as an impairment of dissimilatory iron reduction due to the titration of reactive iron. As a result, bacterial sulfate reduction increased, which consequentially led to a rise in sulfide concentrations.[59]

With the beginning of the Siderian Period, there was an increase in the sulfate concentration of seawater, recognizable by the sulfur-34 isotope (δ34S) values. In the course of bacterial sulfate reduction, this led to significant sulfur isotope fractionations, with an excess amount of sulfate.[60] However, the sulfate concentrations remained at 1–2 millimoles per liter, and were much lower than today's concentrations of 28 millimoles per liter.[61] The cause is now considered to be the increased oxidative weathering on the continents. Rocks spanning 2322±15 million years of age that do not exhibit sulfur-mass independent fractionation indicate that the atmosphere's oxygen concentration had already exceeded 10−5 times the present atmospheric level.[62] At the same time, very strongly negative carbon-13 isotope (δ13C) values in the Lower Timeball Hill Formation of South Africa are considered a definitive indication of the presence of sulfate (anhydrite) in seawater and its bacterial reduction.[63]

References

Citations

  1. ^ Teitler et al. 2014, pp. 71–72.
  2. ^ a b c Yakubchuk, A. S. (July 5, 2019). "From Kenorland to Modern Continents: Tectonics and Metallogeny". Geotectonics. 53: 169–192. Bibcode:2019Geote..53..169Y. doi:10.1134/S0016852119020109. eISSN 1556-1976. ISSN 0016-8521. LCCN sf79010245. OCLC 1751109. S2CID 181748391. Retrieved December 4, 2025.
  3. ^ a b c Plumb, Kenneth A. (June 1991). "New Precambrian time scale". Episodes. 14 (2): 139–140. doi:10.18814/epiiugs/1991/v14i2/005. eISSN 2586-1298. ISSN 0705-3797. LCCN 78646808. OCLC 4130038.
  4. ^ Cowie, John W.; Ziegler, Willi; Remane, Jürgen (June 1989). "Stratigraphic Commission Accelerates Progress, 1984 to 1989" (PDF). Episodes. 12 (2): 79–82. doi:10.18814/epiiugs/1989/v12i2/003. eISSN 2586-1298. ISSN 0705-3797. LCCN 78646808. OCLC 4130038. S2CID 204264548. Archived (PDF) from the original on October 10, 2022. Retrieved December 11, 2025.
  5. ^ Kranendonk, M.J. Van (2012). "A Chronostratigraphic Division of the Precambrian". In Gradstein, Felix M.; Ogg, James G.; Schmitz, Mark D.; Ogg, Gabi M. (eds.). The Geologic Time Scale 2012. Vol. 1. Elsevier. pp. 361–363. ISBN 978-0-44-459390-0. LCCN 2012538100. OCLC 773025121. Retrieved November 29, 2025.
  6. ^ Shields, Graham A.; Strachan, Robin A.; Porter, Susannah M.; Halverson, Galen P.; Macdonald, Francis A.; Plumb, Kenneth A.; Alvarenga, Carlos J. de; Banerjee, Dhiraj M.; Bekker, Andrey; Bleeker, Wouter; Brasier, Alexander; Chakraborty, Partha P.; Collins, Alan S.; Condie, Kent; Das, Kaushik; Evans, David A. D.; Ernst, Richard; Fallick, Anthony E.; Frimmel, Hartwig; Fuck, Reinhardt; Hoffman, Paul F.; Kamber, Balz S.; Kuznetsov, Anton B.; Mitchell, Ross N.; Poiré, Daniel G.; Poulton, Simon W.; Riding, Robert; Sharma, Mukund; Storey, Craig; Stueeken, Eva; Tostevin, Rosalie; Turner, Elizabeth; Xiao, Shuhai; Zhang, Shuanhong; Zhou, Ying; Zhu, Maoyan (July 7, 2021). "A template for an improved rock-based subdivision of the pre-Cryogenian timescale" (PDF). Journal of the Geological Society. 179 (1). Bibcode:2022JGSoc.179..222S. doi:10.1144/jgs2020-222. eISSN 2041-479X. ISSN 0016-7649. LCCN 79641612. OCLC 1934542. S2CID 236285974. Archived (PDF) from the original on January 24, 2025. Retrieved December 11, 2025.
  7. ^ "International Chronostratigraphic Chart" (PDF). International Commission on Stratigraphy. December 2024. Retrieved October 23, 2025.
  8. ^ Kasting, James F.; Ono, Shuehi (June 2006). "Paleoclimates: The First Two Billion Years". Philosophical Transactions: Biological Sciences. 361 (1470): 917–929. doi:10.1098/rstb.2006.1839. eISSN 1471-2970. ISSN 0962-8436. JSTOR 20209693. LCCN 86645785. OCLC 1403239. PMC 1868609. PMID 16754607. S2CID 11582095.
  9. ^ a b c Kopp, Robert E.; Kirschvink, Joseph L.; Hilburn, Isaac A.; Nash, Cody Z. (August 2005). "The Paleoproterozoic Snowball Earth: A climate disaster triggered by the evolution of oxygenic photosynthesis". Proceedings of the National Academy of Sciences of the United States of America. 102 (32): 11131–11136. Bibcode:2005PNAS..10211131K. doi:10.1073/pnas.0504878102. eISSN 1091-6490. ISSN 0027-8424. JSTOR 3376232. LCCN 16010069. OCLC 1607201. PMC 1183582. PMID 16061801. S2CID 467092.
  10. ^ Barley, Bekker & Krapež 2005, pp. 163–164.
  11. ^ Barley, Bekker & Krapež 2005, p. 165.
  12. ^ a b Krapež, Bryan; Barley, Mark E.; Pickard, April L. (October 2003). "Hydrothermal and resedimented origins of the precursor sediments to banded iron formation: sedimentological evidence from the Early Palaeoproterozoic Brockman Supersequence of Western Australia" (PDF). Sedimentology. 50 (5): 979–1011. Bibcode:2003Sedim..50..979K. doi:10.1046/j.1365-3091.2003.00594.x. eISSN 1365-3091. ISSN 0037-0746. LCCN 67003114. OCLC 1765340. S2CID 131361021. Archived from the original (PDF) on August 10, 2017. Retrieved December 10, 2025.
  13. ^ Mojzsis, S. J.; Coath, C. D.; Greenwood, J. P.; McKeegan, K. D.; Harrison, T. M. (May 2003). "Mass-independent isotope effects in Archean (2.5 to 3.8 Ga) sedimentary sulfides determined by ion microprobe analysis" (PDF). Geochimica et Cosmochimica Acta. 67 (9): 1635–1638. doi:10.1016/S0016-7037(03)00059-0. eISSN 1872-9533. ISSN 0016-7037. LCCN 53032712. OCLC 1570626. S2CID 38837378. Archived from the original (PDF) on May 26, 2019. Retrieved December 10, 2025.
  14. ^ Barley, Mark E.; Pickard, April L.; Sylvester, P. J. (January 1997). "Emplacement of a large igneous province as a possible cause of banded iron formation 2.45 billion years ago". Nature. 385: 55–58. Bibcode:1997Natur.385...55B. doi:10.1038/385055a0. eISSN 1476-4687. ISSN 0028-0836. LCCN 12037118. OCLC 1586310. S2CID 4250877. Retrieved November 29, 2025.
  15. ^ McLennan, Simonetti & Goldstein 2000, pp. 265–266.
  16. ^ Al-hashim 2016, p. 9–18.
  17. ^ a b Al-hashim 2016, p. 13–14.
  18. ^ Ross 1981, pp. 4–6, 79.
  19. ^ Al-hashim 2016, p. 17.
  20. ^ Houston & Karlstrom 1992, p. 5–13.
  21. ^ Aspler et al. 2001, p. 291.
  22. ^ Houston & Karlstrom 1992, p. 7–9.
  23. ^ Heaman, L. M. (June 1994). "2.45 Ga Global Mafic Magmatism: Earth's Oldest Superplume?". In Lanphere, M. A.; Dalrymple, G. B.; Turrin, B. D. (eds.). Abstracts of the Eighth International Conference on Geochronology, Cosmochronology, and Isotope Geology. p. 132. ISBN 978-0-7881-1349-9. LCCN 94193205. OCLC 30658967.
  24. ^ Ernst, R.E.; Buchan, K.L. (September 2004). "Igneous rock associations in Canada 3. Large Igneous Provinces (LIPs) in Canada and adjacent regions: 3 Ga to Present". Geoscience Canada. 31 (3): 103–126. eISSN 1911-4850. ISSN 0315-0941. LCCN 74645255. OCLC 1794385. S2CID 128770219. Retrieved November 25, 2025.
  25. ^ Phinney, W. C.; Halls, H. C. (October 2001). "Petrogenesis of the Early Proterozoic Matachewan dyke swarm, Canada, and implications for magma emplacement and subsequent deformation". Canadian Journal of Earth Sciences. 38 (11): 1541–1563. Bibcode:2001CaJES..38.1541P. doi:10.1139/e01-044. eISSN 1480-3313. ISSN 0008-4077. LCCN 65009875. OCLC 2248673. S2CID 128818529. Retrieved November 29, 2025.
  26. ^ Davies, J. H. F. L.; Heaman, L. M. (August 2014). "New U–Pb baddeleyite and zircon ages for the Scourie dyke swarm: A long-lived large igneous province with implications for the Paleoproterozoic evolution of NW Scotland". Precambrian Research. 249: 180–198. Bibcode:2014PreR..249..180D. doi:10.1016/j.precamres.2014.05.007. eISSN 1872-7433. ISSN 0301-9268. LCCN 74642650. OCLC 1792859. S2CID 129801187. Retrieved November 30, 2025.
  27. ^ Smirnov, Aleksey V.; Evans, David A. D.; Ernst, Richard E.; Söderlund, Ulf; Li, Zheng-Xiang (January 2013). "Trading partners: Tectonic ancestry of southern Africa and western Australia, in Archean supercratons Vaalbara and Zimgarn" (PDF). Precambrian Research. 224: 11–22. Bibcode:2013PreR..224...11S. doi:10.1016/j.precamres.2012.09.020. eISSN 1872-7433. ISSN 0301-9268. LCCN 74642650. OCLC 1792859. S2CID 128901141. Archived (PDF) from the original on June 12, 2024. Retrieved December 10, 2025.
  28. ^ Aspler et al. 2001, p. 287.
  29. ^ Bekker, Andrey; Eriksson, Kenneth A. (February 10, 2003). "A Paleoproterozoic drowned carbonate platform on the southeastern margin of the Wyoming Craton: a record of the Kenorland breakup" (PDF). Precambrian Research. 120 (3–4): 327–364. Bibcode:2003PreR..120..327B. doi:10.1016/S0301-9268(02)00165-1. eISSN 1872-7433. ISSN 0301-9268. LCCN 74642650. OCLC 1792859. S2CID 128917263. Archived from the original (PDF) on August 24, 2015. Retrieved December 10, 2025.
  30. ^ Houston & Karlstrom 1992, pp. 5–7.
  31. ^ Daly, J. Stephen; Balagansky, Victor V.; Timmerman, Martin J.; Whitehouse, Martin J. (2006). "The Lapland-Kola orogen: Palaeoproterozoic collision and accretion of the northern Fennoscandian lithosphere". In Gee, D. G.; Stephenson, R. A. (eds.). European Lithosphere Dynamics. Vol. 32. Geological Society of London. pp. 579–598. Bibcode:2006GSLMm..32..579D. doi:10.1144/GSL.MEM.2006.032.01.35. ISBN 978-1-86239-212-0. LCCN 2007274602. OCLC 78202548. S2CID 129511509.
  32. ^ Astaf'ev, B. Yu.; Levchenkov, O. A.; Rizanova, N. G.; Voinova, O. A.; Voinov, A. S.; Levskii, L. K.; Makeev, A. F.; Lokhov, K. I. (March 2010). "Geological Structure and Isotopic–Geochronologic Study of Rocks from the Strel'na Segment of the Terskii Greenstone Belt, Kola Peninsula". Stratigraphy and Geological Correlation. 18 (1): 1–15. Bibcode:2010SGC....18....1A. doi:10.1134/S0869593810010016. eISSN 1555-6263. ISSN 0869-5938. LCCN 93641701. OCLC 29573835. S2CID 140562071. Retrieved December 7, 2025.
  33. ^ Teitler et al. 2014, p. 78.
  34. ^ Catling, David C.; Zahnle, Kevin J. (February 26, 2020). "The Archean atmosphere". Science Advances. 6 (9). American Association for the Advancement of Science. Bibcode:2020SciA....6.1420C. doi:10.1126/sciadv.aax1420. eISSN 2375-2548. PMC 7043912. PMID 32133393. S2CID 212116079.
  35. ^ Tang, Haoshu; Chen, Yanjing (September 2013). "Global glaciations and atmospheric change at ca. 2.3 Ga". Geoscience Frontiers. 4 (5): 583–596. Bibcode:2013GeoFr...4..583T. doi:10.1016/j.gsf.2013.02.003. eISSN 2588-9192. ISSN 1674-9871. LCCN 2012211273. OCLC 818646078. S2CID 128423355.
  36. ^ Holland, Heinrich D. (November 2002). "Volcanic gases, black smokers, and the great oxidation event" (PDF). Geochimica et Cosmochimica Acta. 66 (21): 3811–3826. Bibcode:2002GeCoA..66.3811H. doi:10.1016/S0016-7037(02)00950-X. eISSN 1872-9533. ISSN 0016-7037. LCCN 53032712. OCLC 1570626. S2CID 38541908. Archived from the original (PDF) on May 21, 2023. Retrieved December 11, 2025.
  37. ^ Holland, Heinrich D.; Karhu, Juha A. (October 1996). "Carbon isotopes and the rise of atmospheric oxygen". Geology. 24 (10): 867–870. Bibcode:1996Geo....24..867K. doi:10.1130/0091-7613(1996)024<0867:CIATRO>2.3.CO;2. eISSN 1943-2682. ISSN 0091-7613. LCCN 73645581. OCLC 1788177. S2CID 129655228. Retrieved December 2, 2025.
  38. ^ Barley, Bekker & Krapež 2005, p. 157.
  39. ^ Barley, Bekker & Krapež 2005, pp. 159, 167–169.
  40. ^ Papineau, Dominic (March 2010). "Global Biogeochemical Changes at Both Ends of the Proterozoic: Insights from Phosphorites". Astrobiology (PDF). 10 (2): 165–181. Bibcode:2010AsBio..10..165P. doi:10.1089/ast.2009.0360. eISSN 1557-8070. ISSN 1531-1074. LCCN 00213943. OCLC 44648498. PMID 20105035. S2CID 40860636. Retrieved December 2, 2025.
  41. ^ Teitler et al. 2014, pp. 76–78.
  42. ^ Teitler et al. 2014, pp. 73, 76.
  43. ^ Teitler et al. 2014, p. 71.
  44. ^ a b c d e Pehrsson et al. 2014, p. 807.
  45. ^ Hoffman 2013, p. 150.
  46. ^ Hoffman 2013, p. 145.
  47. ^ Brasier, A. T.; Martin, A. P.; Melezhik, V. A.; Prave, A. R.; Condon, D. J.; Fallick, A. E.; FAR-DEEP Scientists (September 2013). "Earth's earliest global glaciation? Carbonate geochemistry and geochronology of the Polisarka Sedimentary Formation, Kola Peninsula, Russia". Precambrian Research. 235. Elsevier: 278–294. Bibcode:2013PreR..235..278B. doi:10.1016/j.precamres.2013.06.007. eISSN 1872-7433. ISSN 0301-9268. LCCN 74642650. OCLC 1792859. S2CID 53008028. Retrieved December 9, 2025.
  48. ^ Hoffman 2013, pp. 151–152.
  49. ^ Hoffman 2013, p. 151.
  50. ^ Hoffman 2013, pp. 145, 150, 152.
  51. ^ Boden, Joanne S.; Nieves-Morión, Mercedes; Nürnberg, Dennis J.; Arévalo, Sergio; Flores, Enrique; Sánchez-Baracaldo, Patricia (November 27, 2025). "Evolution of multicellularity genes in Cyanobacteria in the lead up to the great oxidation event". Communications Biology. 8 1721. Springer Nature. doi:10.1038/s42003-025-09247-6. eISSN 2399-3642. PMC 12669612. PMID 41309968. S2CID 283350357.
  52. ^ Hedges, S. Blair; Blair, Jaime E.; Venturi, Maria L.; Shoe, Jason L. (January 28, 2004). "A molecular timescale of eukaryote evolution and the rise of complex multicellular life". BMC Evolutionary Biology. 4 2. doi:10.1186/1471-2148-4-2. eISSN 2730-7182. PMC 341452. PMID 15005799.
  53. ^ Knoll, Andrew H.; Holland, Heinrich D. (1995). "Oxygen and Proterozoic Evolution: An Update". Effects of Past Global Change on Life. National Academy Press. p. 27. ISBN 978-0-309-05127-9. LCCN 94038695. OCLC 42854432. NBK 231936.
  54. ^ Barlow, Erica Victoria; Kranendonk, Martin Julian Van (August 9, 2018). "Snapshot of an early Paleoproterozoic ecosystem: Two diverse microfossil communities from the Turee Creek Group, Western Australia" (PDF). Geobiology. 16: 449–475. Bibcode:2018Gbio...16..449B. doi:10.1111/gbi.12304. eISSN 1472-4669. ISSN 1472-4677. LCCN 2003201710. OCLC 52805553. PMID 30091832. S2CID 51939442. Retrieved December 14, 2025.
  55. ^ Shixing & Huineng 1992, p. 138.
  56. ^ Melezhik, Victor A.; Fallick, Anthony E.; Makarikhin, Vladimir V.; Lyubtsov, Valery V. (April 1997). "Links between Palaeoproterozoic palaeogeography and rise and decline of stromatolites: Fennoscandian Shield". Precambrian Research. 82 (3–4). Elsevier: 311–348. Bibcode:1997PreR...82..311M. doi:10.1016/S0301-9268(96)00061-7. eISSN 1872-7433. ISSN 0301-9268. LCCN 74642650. OCLC 1792859. S2CID 129096718. Retrieved December 14, 2025.
  57. ^ Rouxel, Olivier J.; Bekker, Andrey; Edwards, Katrina J. (February 18, 2005). "Iron Isotope Constraints on the Archean and Paleoproterozoic Ocean Redox State". Science. 307 (5712): 1088–1091. Bibcode:2005Sci...307.1088R. doi:10.1126/science.1105692. ISSN 0036-8075. JSTOR 3840158. LCCN 17024346. OCLC 1644869. PMID 15718467. S2CID 44539602.
  58. ^ Anbar, Ariel D.; Rouxel, Olivier J. (May 2007). "Metal Stable Isotopes in Paleoceanography" (PDF). Annual Review of Earth and Planetary Sciences. 35: 717–746. Bibcode:2007AREPS..35..717A. doi:10.1146/annurev.earth.34.031405.125029. eISSN 1545-4495. ISSN 0084-6597. LCCN 72082137. OCLC 1783648. S2CID 130960654. Archived (PDF) from the original on November 2, 2024. Retrieved December 11, 2025.
  59. ^ Johnson, Clark M.; Beard, Brian L.; Roden, Eric E. (May 2008). "The Iron Isotope Fingerprints of Redox and Biogeochemical Cycling in Modern and Ancient Earth" (PDF). Annual Review of Earth and Planetary Sciences. 36: 457–493. Bibcode:2008AREPS..36..457J. doi:10.1146/annurev.earth.36.031207.124139. eISSN 1545-4495. ISSN 0084-6597. LCCN 72082137. OCLC 1783648. S2CID 53393255. Archived (PDF) from the original on April 13, 2024. Retrieved December 11, 2025.
  60. ^ Canfield, D. E. (January 2001). "Biogeochemistry of Sulfur Isotopes". Reviews in Mineralogy and Geochemistry. 43 (1): 607–636. Bibcode:2001RvMG...43..607C. doi:10.2138/gsrmg.43.1.607. eISSN 1943-2666. ISSN 1529-6466. LCCN 00214630. OCLC 43835968. S2CID 98812140. Retrieved November 27, 2025.
  61. ^ Kah, Linda C.; Lyons, Timothy W.; Frank, Tracy D. (October 14, 2004). "Low marine sulphate and protracted oxygenation of the Proterozoic biosphere" (PDF). Nature. 431: 834–838. Bibcode:2004Natur.431..834K. doi:10.1038/nature02974. eISSN 1476-4687. ISSN 0028-0836. LCCN 12037118. OCLC 1586310. PMID 15483609. S2CID 4404486. Archived from the original (PDF) on June 17, 2010. Retrieved November 27, 2025.
  62. ^ Bekker, Andrey; Holland, Heinrich D.; Wang, P.-L.; Rumble III, D.; Stein, H. J.; Hannah, J. L.; Coetzee, L. L.; Beukes, N. J. (January 8, 2004). "Dating the rise of atmospheric oxygen". Nature. 427: 117–120. Bibcode:2004Natur.427..117B. doi:10.1038/nature02260. eISSN 1476-4687. ISSN 0028-0836. LCCN 12037118. OCLC 1586310. PMID 14712267. S2CID 4329872. Retrieved November 27, 2025.
  63. ^ Cameron, E. M. (July 1983). "Evidence from early Proterozoic anhydrite for sulphur isotopic partitioning in Precambrian oceans". Nature. 304: 54–56. Bibcode:1983Natur.304...54C. doi:10.1038/304054a0. eISSN 1476-4687. ISSN 0028-0836. LCCN 12037118. OCLC 1586310. S2CID 4274243. Retrieved November 27, 2025.

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