Wuliuan
{{short description|Fifth stage of Cambrian and first stage of the Miaolingian}}
{{Infobox geologic timespan
| name = Wuliuan
| color = Wuliuan
| time_start = 506.5
| time_start_prefix = ~
| time_end = 504.5
| time_end_prefix = ~
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| timeline = Cambrian
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| name_formality = Formal
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| former_names = Cambrian Stage 5
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| celestial_body = earth
| usage = Global (ICS)
| timescales_used = ICS Time Scale
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| chrono_unit = Age
| strat_unit = Stage
| timespan_formality = Formal
| lower_boundary_def = FAD of Oryctocephalus indicus.
| lower_gssp_location = Wuliu-Zengjiayan, Guizhou, China
| lower_gssp_coords = {{Coord|26.0807|N|108.4138|E|display=inline}}
| lower_gssp_accept_date = 2018
| upper_boundary_def = FAD of the Trilobite Ptychagnostus atavus
| upper_gssp_location = Drumian section, Wheeler Shale, Utah, U.S.A.
| upper_gssp_coords = {{Coord|39.5117|N|112.9915|W|display=inline}}
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The Wuliuan stage is the fifth stage of the Cambrian, and the first stage of the Miaolingian Series of the Cambrian. It was formally defined by the International Commission on Stratigraphy in 2018.{{cite web|url=http://www.stratigraphy.org/icschart/ChronostratChart2018-08.pdf|title=ChronostratChart2018-08|publisher=International Commission on Stratigraphy|archive-url=https://web.archive.org/web/20180731123434/http://www.stratigraphy.org/icschart/ChronostratChart2018-08.pdf|archive-date=31 July 2018|url-status=dead}}
Its base is defined by the first appearance of the trilobite species Oryctocephalus indicus; it ends with the beginning of the Drumian Stage, marked by the first appearance of the trilobite Ptychagnostus atavus around {{Period start|Drumian}} million years ago.{{cite web|title=GSSP Table - Paleozoic Era|url=https://engineering.purdue.edu/Stratigraphy/gssp/index.php?parentid=77|access-date=2024-03-28|archive-url=https://web.archive.org/web/20231008002417/https://timescalefoundation.org/gssp/index.php?parentid=77|archive-date=2023-10-08|url-status=live}}
The 'golden spike' that formally defines the base of the age is driven into the Wuliu-Zengjiayan (乌溜-曾家崖) section of the Kaili formation, near Balang Village in the Miaoling Mountains, Guizhou, China.{{cite web |last1=Ahlberg |first1=Per |last2=Babcock |first2=Loren E. |title=Subcommission on Cambrian Stratigraphy Annual Report 2017 |url=http://www.palaeontology.geo.uu.se/ISCS/ISCS%20Annual%20Report%202017.pdf |publisher=International Commission on Stratigraphy |access-date=2024-03-28|archive-url=https://web.archive.org/web/20230716074543/http://www.palaeontology.geo.uu.se/ISCS/ISCS%20Annual%20Report%202017.pdf|archive-date=2023-07-16|url-status=live}}
GSSP
Three sections were discussed as GSSP candidates: the Wuliu-Zengjiayan section near Balang in Guizhou province (China), a section on Split Mountain in Nevada (USA){{cite web|author=F. M. Gradstein, J. G. Ogg, M. D. Schmitz, G. M. Ogg|url=https://engineering.purdue.edu/Stratigraphy/gssp/index.php?parentid=77|title=The Geologic Time Scale 2012|website=The Geologic Time Scale| archive-url=https://web.archive.org/web/20131021195812/https://engineering.purdue.edu/Stratigraphy/gssp/index.php?parentid=77 | archive-date=2013-10-21 }} and the "Molodo river section" along the Molodo river (Sakha Republic, Russia).{{cite journal|title=The 13th International Field Conference of the Cambrian Stage Subdivision Working Group|journal=Episodes|volume=31|issue=4|pages=440–441|url=http://www.episodes.co.in/www/backissues/314/440-442%20Confreport-Russia,%202%20(3).pdf|access-date=2024-03-28|archive-url=https://web.archive.org/web/20141105184944/http://www.episodes.co.in/www/backissues/314/440-442%20Confreport-Russia,%202%20(3).pdf|archive-date=2014-11-05|url-status=dead}} The Wuliu-Zengjiayan section is an outcrop of the Kaili Formation in the Wuliu quarry. The first candidate for the beginning of the Wuliuan was the trilobite Oryctocephalus indicus, the second candidate was the trilobite Ovatoryctocara granulata.{{cite journal|last=Sundberg|first=F.A.|author2=Zhao, Y.L. |author3=Yuan, J.L. |author4= Lin, J.P. |date=22 September 2011|title=Detailed trilobite biostratigraphy across the proposed GSSP for Stage 5 ("Middle Cambrian" boundary) at the Wuliu-Zengjiayan section, Guizhou, China|journal=Bulletin of Geosciences|volume=86|issue=3|pages=423–464|doi=10.3140/bull.geosci.1211|doi-access=free}}
The Wuliu-Zengjiayan section was chosen as the formal base in 2018, with the first appearance of Oryctocephalus indicus being chosen as the defining marker for the GSSP.
Major events
The base of Wuliuan stage (and, accordingly, the entire Miaolingian Series) is characterized by the first major extinction of trilobites, known as the Olenellid Biomere boundary. This event is linked by a sudden negative carbonate carbon excursion.{{cite journal|author=Jih-Pai Lin, Frederick A. Sundberg, Ganqing Jiang, Isabel P. Montañez, Thomas Wotte|date=22 November 2019|title=Chemostratigraphic correlations across the first major trilobite extinction and faunal turnovers between Laurentia and South China|journal=Scientific Reports|volume=9|issue=1|page=17392|doi=10.1038/s41598-019-53685-2|pmid=31758094 |pmc=6874646|bibcode=2019NatSR...917392L }}
Paleontology
Benthic graptolites have reached a considerable diversity im the Wuliuan. The most common graptolite genus of this age is Sphenoecium, whose robust colonies were found all over the world.{{cite journal|author=Jörg Maletz|date=8 December 2023|url=https://www.researchgate.net/publication/376365387|title=Benthic graptolites (Graptolithina, Pterobranchia) in the Miaolingian (Cambrian Series 3)|journal=Palaeobiodiversity and Palaeoenvironments|volume=104 |issue=2 |pages=259–274 |doi=10.1007/s12549-023-00595-x|doi-access=free}} Numerous panarthropods, including trilobites, agnostoids, hurdiids and bradoriids, are known from Wuliuan deposits.{{cite journal|author=Julien Kimmig, Stephen Pates, Rhiannon J. LaVine, L. J. Krumenacker, Anna F. Whitaker, Luke C. Strotz, Paul G. Jamison, Val G. Gunther, Glade Gunther, Matt Witte, Allison C. Daley, Bruce S. Lieberman|year=2023|url=https://www.researchgate.net/publication/369568164|title=New soft-bodied panarthropods from diverse Spence Shale (Cambrian; Miaolingian; Wuliuan) depositional environments|journal=Journal of Paleontology|volume=97|issue=5|pages=1025–1048|doi=10.1017/jpa.2023.24|doi-access=free|bibcode=2023JPal...97.1025K }}
References
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External links
- {{cite web|url=https://timescalefoundation.org/gssp/image.php?periodid=150&top_parentid=77&imageid=432|title=Combined Image for Wuliuan Stage: GSSP of the Miaolingian Series and Wuliuan Stage in the Wului-Zengjiayan Section, Guizhou, China|website=Geologic Timescale Foundation|archive-url=https://web.archive.org/web/20220526074951/https://timescalefoundation.org/gssp/image.php?periodid=150&top_parentid=77&imageid=432|archive-date=2022-05-26|url-status=live}}
- {{cite journal |author=Yuanlong Zhao |author2=Jinliang Yuan |author3=Loren E. Babcock |author4=Qingjun Guo |author5=Jin Peng |author6=Leiming Yin |author7=Xinglian Yang |author8=Shanchi Peng |author9=Chunjiang Wang |author10=Robert R. Gaines |author10link=Robert R. Gaines |author11=Jorge Esteve |author12=Tongsu Tai |author13=Ruidong Yang |author14=Yue Wang |author15=Haijing Sun |author16=Yuning Yang |title=Global Standard Stratotype-Section and Point (GSSP) for the conterminous base of the Miaolingian Series and Wuliuan Stage (Cambrian) at Balang, Jianhe, Guizhou, China |journal=Episodes |date=June 2019 |volume=42 |issue=2 |pages=165–184 |doi=10.18814/epiiugs/2019/019013 |url=http://www.palaeontology.geo.uu.se/ISCS/Miaolingian%20and%20Wuliuan%20GSSP.pdf |access-date=2024-03-28|doi-access=free|archive-url=https://web.archive.org/web/20220304072741/http://www.palaeontology.geo.uu.se/ISCS/Miaolingian%20and%20Wuliuan%20GSSP.pdf|archive-date=2022-03-04|url-status=live }}
- {{cite web|url=http://www.palaeontology.geo.uu.se/ISCS/ISCS_GSSPs.html|title=GSSPs - The Cambrian System 2019|publisher=International Commission on Stratigraphy|lang=en|archive-url=https://web.archive.org/web/20230721165125/http://www.palaeontology.geo.uu.se/ISCS/ISCS_GSSPs.html|archive-date=2023-07-21|url-status=live}}
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