Wikipedia

Jiangshanian

28°48′57″N 118°36′54″E / 28.815967°N 118.614933°E / 28.815967; 118.614933

Jiangshanian
~494 – ~489.5 Ma
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Chronology
Etymology
Name formalityFormal
Name ratified2011[2]
Former name(s)Cambrian Stage 9
Usage information
Celestial bodyEarth
Regional usageGlobal (ICS)
Time scale(s) usedICS Time Scale
Definition
Chronological unitAge
Stratigraphic unitStage
Time span formalityFormal
Lower boundary definitionFAD of the Trilobite Agnostotes orientalis
Lower boundary GSSPDuibian B Section, Duibian, Zhejiang, China
28°48′57″N 118°36′54″E / 28.815967°N 118.614933°E / 28.815967; 118.614933
Lower GSSP ratified2011[2]
Upper boundary definitionNot formally defined
Upper boundary definition candidatesFAD of the Trilobite Lotagnostus americanus
Upper boundary GSSP candidate section(s)Duibian, Zhejiang, China

The Jiangshanian is the middle stage of the Furongian series. It follows the Paibian Stage and is succeeded by the still unnamed Stage 10 of the Cambrian. The base is defined as the first appearance of the trilobite Agnostotes orientalis[3] which is estimated to be 494 million years ago. The Jiangshanian lasted until approximately 489.5 million years ago.[4]

The Jiangshanian stage was named after Jiangshan, a city in China's Zhejiang province, where its GSSP was defined.[2]

Stratigraphy

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The Global boundary Stratotype Section and Point (GSSP) of the Jiangshanian is the "Duibian B Section" (28°48′57″N 118°36′54″E / 28.815967°N 118.614933°E / 28.815967; 118.614933), west of the village of Duibian (碓边), and 10 km north of Jiangshan. The outcrop belongs to the Huayansi Formation (华严寺组).[3] The upper boundary (the base of the Stage 10) is not formally defined by ICS, but there is a proposal to set the first appearance of an agnostoid Lotagnostus americanus as its marker.[5]

In 2012, international research group proposed the Kyrshabakty section in the Malyi Karatau Range, southern Kazakhstan, as a candidate for the Auxiliary boundary Stratotype Section and Point (ASSP) of the Jiangshanian. The proposal was approved by an overwhelming majority of votes by the International Subcommission on Cambrian Stratigraphy (ISCS). The section is situated near Kyrshabakty River, about 28 km north-east of the Zhanatas town. The first appearance datum (FAD) of Agnostotes orientalis is located at an altitude of 259 m above the base of the section, in the Zhumabay Formation, also known as Bestogai Formation.[6] In 2021, the International Union of Geological Sciences (IUGS) proposed to deny the use of specific points and replace them by Standard Auxiliary Boundary Stratotypes (SABS) for more "flexible" correlations with GSSPs.[7]

Major events

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At the beginning of the Jiangshanian, there was a peak in species diversity, comparable to that observed in the middle Guzhangian, before the Guzhangian–Paibian extinction. Jiangshanian extinction, which lasted approximately from 493.9 to 491.3 Ma, reduced species diversity by 55.2%. It was followed by an interval of relatively small fluctuations in species richness, which ended shortly after the beginning of the Ordovician.[8]

Paleontology

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Nearly 50 fossil genera were found in the Jiangshanian deposits of the Sandu Formation in Guangxi, South China. Organisms presented by the algae, graptolites, the cnidarian Sphenothallus, one species of Palaeoscolecida, and arthropods, which include aglaspidid, mollisoniid, and "bivalved" forms.[9] Rare hurdiids were discovered in the Jiangshanian strata in Sandu Formation and Wiśniówka Sandstone Formation in Poland.[9][10] Trilobites Parabolina, Hedinaspis, Eugonocare and Cermatops, with agnostoid genera including Pseudagnostus and Rhaptagnostus, were collected from the Jiangshanian sediments of western Tasmania.[11] Trilobite genera Monocheilus, Ptychaspis and Wilbernia are known from the Jiangshanian Honey Creek Formation in the Wichita Mountains, Oklahoma, USA.[12]

References

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  1. ^ "International Chronostratigraphic Chart" (PDF). International Commission on Stratigraphy. September 2023. Retrieved November 10, 2024.
  2. ^ a b c Peng, Shanchi; Babcock, Loren; Zuo, Jingxun; Lin, Huanling; Yang, Xianfeng; Qi, Yuping; Bagnoli, Gabriella; Wang, Longwu (December 2012). "Global Standard Stratotype-Section and Point (GSSP) for the Base of the Jiangshanian Stage (Cambrian: Furongian) at Duibian, Jiangshan, Zhejiang, Southeast China" (PDF). Episodes. 35 (4): 462–477. doi:10.18814/epiiugs/2012/v35i4/002. Archived (PDF) from the original on 2024-04-04. Retrieved 2024-04-07.
  3. ^ a b "GSSP for Jiangshanian". Archived from the original on 2023-01-24. Retrieved 2024-04-07.
  4. ^ "Latest version of international chronostratigraphic chart". International Commission on Stratigraphy. Retrieved 2024-04-07.
  5. ^ "ISCS Working Groups: Working Group on the Stage 10 GSSP". International Subcommission on Cambrian Stratigraphy. Archived from the original on 2023-09-26.
  6. ^ Gappar Kh. Ergaliev, Vyacheslav (Slava) G. Zhemchuzhnikov, Leonid E. Popov, Michael G. Bassett, Farkhat G. Ergaliev (2014). "The Auxiliary boundary Stratotype Section and Point (ASSP) of the Jiangshanian Stage (Cambrian: Furongian Series) in the Kyrshabakty section". Episodes. 37 (1): 41—47. doi:10.18814/epiiugs/2014/v37i1/005.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  7. ^ Martin J. Head, Marie-Pierre Aubry, Werner E. Piller, Mike Walker (2023). "The Standard Auxiliary Boundary Stratotype: a proposed replacement for the Auxiliary Stratotype Point in supporting a Global boundary Stratotype Section and Point (GSSP)" (PDF). Episodes. 46 (1): 35—45. doi:10.18814/epiiugs/2022/022012. Archived (PDF) from the original on 2024-02-02. Retrieved 2024-04-07.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  8. ^ Yiying Deng, Junxuan Fan, Shengchao Yang, Yukun Shi, Zhengbo Lu, Huiqing Xu, Zongyuan Sun, Fangqi Zhao, Zhangshuai Hou (2023). "No Furongian Biodiversity Gap: Evidence from South China". Palaeogeography, Palaeoclimatology, Palaeoecology. 618 (1): 111492. Bibcode:2023PPP...61811492D. doi:10.1016/j.palaeo.2023.111492.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  9. ^ a b Xuejian Zhu, Rudy Lerosey-Aubril, Javier Ortega-Hernández (2021). "Furongian (Jiangshanian) occurrences of radiodonts in Poland and South China and the fossil record of the Hurdiidae". PeerJ. 9 (e11800): 1—23. doi:10.7717/peerj.11800. PMC 8312493. PMID 34386302.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  10. ^ Gaëtan J-M Potin, Allison C. Daley (2023). "The significance of Anomalocaris and other Radiodonta for understanding paleoecology and evolution during the Cambrian explosion". Frontiers in Earth Science. 11: 1—26. Bibcode:2023FrEaS..1160285P. doi:10.3389/feart.2023.1160285.
  11. ^ Christopher J. Bentley, James B. Jago, Keith Corbett (2020). "Late Cambrian (Iverian, Jiangshanian) fossils from the Professor Range area, Western Tasmania". Alcheringa: An Australasian Journal of Palaeontology. 44 (2): 1—14. Bibcode:2020Alch...44..203B. doi:10.1080/03115518.2020.1725833.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  12. ^ Sean R. Blackwell, Stephen R. Westrop (2023). "A new Cambrian (Jiangshanian, Sunwaptan) trilobite fauna from Oklahoma and its biostratigraphic significance". Journal of Paleontology. 97 (4): 865. Bibcode:2023JPal...97..865B. doi:10.1017/jpa.2023.40.
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