Ectasian
| Ectasian | ||||||
|---|---|---|---|---|---|---|
 Map of Earth in the late Ectasian, c. 1260 Ma | ||||||
| Chronology | ||||||
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| Etymology | ||||||
| Name formality | Formal | |||||
| Usage information | ||||||
| Celestial body | Earth | |||||
| Regional usage | Global (ICS) | |||||
| Time scale(s) used | ICS Time Scale | |||||
| Definition | ||||||
| Chronological unit | Period | |||||
| Stratigraphic unit | System | |||||
| Time span formality | Formal | |||||
| Lower boundary definition | Defined chronometrically | |||||
| Lower GSSA ratified | 1990[1] | |||||
| Upper boundary definition | Defined chronometrically | |||||
| Upper GSSA ratified | 1990[1] | |||||
The Ectasian Period (from Ancient Greek: ἔκτασις, romanized: éktasis, meaning "extension") is the second geologic period in the Mesoproterozoic Era and lasted from 1400 Mya to 1200 Mya (million years ago). Instead of being based on stratigraphy, these dates are defined chronometrically.
Geologically, the name refers to the continued expansion of platform covers during this period. In the early Ectasian period, a day was 17 hours and 32 minutes. At the end of the Ectasian, it was 18 hours and 28 minutes.
Geology
The early Ectasian has the supercontinent Columbia intact until at least 1.35 Ga with rifting around the western side of Laurentia.[2] Columbia slowly destabilized until it fully broke up around 1.3-1.2 Ga at the mid to end Ectasian with multiple dyke swarms including the Mackenzie dike swarm at in Canada and the Galiwinku dyke swarm in Australia.[2][3] Evidence from metamafic rocks from 1.37 to 1.35 Ga suggests that a superplume formed around that time and affected 3 provinces, causing expansion and the breakup of Columbia.[4]
Biology
The Dismal Lakes group ranging from 1590 to 1270 Mya hosts microfossils that are interpreted to be eukaryotes, with various species appearing in the grouping.[5]
Continued appearances of acritarchs are present in the Ectasian period with a moderate amount of eukaryotes.[6]
Climate
The very beginning of the Ectasian had the end of the Mesoproterozoic Oxidation Event which lasted from 1.59 to 1.36 Ga, with estimations going up to 3.6% current levels of oxygen.[7][8] Besides this, the Ectasian had oxygen conditions typical of the Boring Billion, from 0.1% to 1% of current oxygen levels in most conditions.[9]
The seafloor during the Ectasian is around 50-80% oxidated at the beginning of the period and declined afterwards.[7] The ocean was mostly ferruginous in lower depths with a minority surface area being oxic and recurring euxinic conditions in mid-depth waters.[7]
The water temperature during the Mesoproterozoic is reported to be 26.9 ± 0.4 degrees Celsius with the water being lighter than the current ocean water.[10] Shallow seafloors may have "oxygen oases" by microbial mats oxygenating the seafloor, allowing aerobic organisms to survive.[11]
See also
- Boring Billion – Earth history, 1.8 to 0.8 billion years ago
- Jotnian – Oldest known sediments in the Baltic area that have not been subject to metamorphism
- Riphean age – Stage in the geological timescale named after the Urals
References
- ^ a b 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. S2CID 126954461.
- ^ a b Zhao, G.; Sun, M.; Wilde, S. A.; Li, S. (2004). "A Paleo-Mesoproterozoic supercontinent: assembly, growth and breakup". Earth-Science Reviews. 67 (1): 91–123. Bibcode:2004ESRv...67...91Z. doi:10.1016/j.earscirev.2004.02.003. Retrieved 14 February 2016.
- ^ Hou, Guiting; Santosh, M.; Qian, Xianglin; Lister, Gordon S.; Li, Jianghai (2008-10-01). "Tectonic constraints on 1.3-1.2 Ga final breakup of Columbia supercontinent from a giant radiating dyke swarm". Gondwana Research. 14 (3): 561–566. doi:10.1016/j.gr.2008.03.005. ISSN 1342-937X.
- ^ Lv, Pei; Yu, Shengyao; Peng, Yinbiao; Wang, Chunyu; Li, Sanzhong; Liu, Yongjiang; Gao, Xiangyu; Sun, Deyou; Jiang, Xingzhou; Ji, Wentao; Li, Chuanzhi; Wang, Lintao; Qi, Yu (2022-08-01). "A plume broke up Columbia supercontinent: Evidence from the Mesoproterozoic metamafic rocks in the Tarim Craton, NW China". Precambrian Research. 377 106719. doi:10.1016/j.precamres.2022.106719. ISSN 0301-9268.
- ^ Loron, Corentin C.; Halverson, Galen P.; Rainbird, Robert H.; Skulski, Thomas (July 2021). "Shale-hosted biota from the Dismal Lakes Group in Arctic Canada supports an early Mesoproterozoic diversification of eukaryotes". ResearchGate. Retrieved March 27, 2026.
- ^ Knoll, Andrew H., Emmanuelle J. Javaux, David Hewitt, and Phoebe A. Cohen. 2006. Eukaryotic organisms in Proterozoic oceans. Philosophical Transactions- Royal Society of London Series B Biological Sciences 361(1470): 1023-1038. https://doi.org/10.1098/rstb.2006.1843
- ^ a b c Yan, Hao; Qin, Zheng; Xu, Lingang; Mao, Jingwen; Tang, Dongjie; Huang, Qin; Yang, Xiuqing; Li, Zhiquan; Li, Jie; Li, Long; Robbins, Leslie J.; Kendall, Brian; Canfield, Donald E.; Konhauser, Kurt O. (2025-11-26). "An expansive global oxygenation of Earth's surface environments 1.4 billion years ago". Nature Communications. 16 (1): 10535. doi:10.1038/s41467-025-65551-z. ISSN 2041-1723.
- ^ Zhang, Shuichang; Wang, Huajian; Wang, Xiaomei; Ye, Yuntao (25 October 2021). "The Mesoproterozoic Oxygenation Event". Science China Earth Sciences. 64 (12): 2043–2068. Bibcode:2021ScChD..64.2043Z. doi:10.1007/s11430-020-9825-x. S2CID 239891560. Retrieved 9 May 2023.
- ^ Planavsky, Noah J.; Cole, Devon B.; Isson, Terry T.; Reinhard, Christopher T.; Crockford, Peter W.; Sheldon, Nathan D.; Lyons, Timothy W. (9 August 2018). "A case for low atmospheric oxygen levels during Earth's middle history". Emerging Topics in Life Sciences. 2 (2): 149–159. doi:10.1042/etls20170161. ISSN 2397-8554. PMID 32412619. S2CID 210099422.
- ^ "Science". AAAS. doi:10.1126/sciadv.adu6693. PMC 12533587. PMID 41105769. Retrieved 2026-03-28.
- ^ Jia, Tianyi; Wang, Ruimin; Huang, Tianzheng; Lang, Xianguo; Ma, Haoran; Shen, Bing (2022-07-15). "Constraining the redox landscape of Mesoproterozoic mat grounds: A possible oxygen oasis in the 'Boring Billion' seafloor". Precambrian Research. 376 106681. doi:10.1016/j.precamres.2022.106681. ISSN 0301-9268.
Further reading
- James G. Ogg (2004). "Status on Divisions of the International Geologic Time Scale". Lethaia. 37 (2): 183–199. doi:10.1080/00241160410006492.
| Cenozoic Era (present–66.0 Ma) |
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| Mesozoic Era (66.0–252 Ma) |
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| Paleozoic Era (252–539 Ma) |
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| Proterozoic Eon (539 Ma–2.5 Ga) |
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| Archean Eon (2.5–4 Ga) | |||||||||||||
| Hadean Eon (4–4.6 Ga) | |||||||||||||
ka = kiloannum (thousand years ago); Ma = megaannum (million years ago); Ga = gigaannum (billion years ago). See also: Geologic time scale •  Geology portal •  World portal | |||||||||||||