Furongian

Last updated
Furongian
~497 – 485.4 ± 1.9 Ma
Chronology
Etymology
Name formalityFormal
Name ratified2003
Former name(s)Cambrian Series 4
Usage information
Celestial body Earth
Regional usageGlobal (ICS)
Time scale(s) usedICS Time Scale
Definition
Chronological unit Epoch
Stratigraphic unit Series
First proposed byShanchi et al., 2002 [2]
Time span formalityFormal
Lower boundary definition FAD of the Trilobite Glyptagnostus reticulatus
Lower boundary GSSPPaibi section, Paibi, Hunan, China
28°23′22″N109°31′33″E / 28.3895°N 109.5257°E / 28.3895; 109.5257
Lower GSSP ratified2003 [3]
Upper boundary definitionFAD of the Conodont Iapetognathus fluctivagus .
Upper boundary GSSPGreenpoint section, Green Point, Newfoundland, Canada
49°40′58″N57°57′55″W / 49.6829°N 57.9653°W / 49.6829; -57.9653
Upper GSSP ratified2000 [4]

The Furongian is the fourth and final epoch and series of the Cambrian. It lasted from 497 to 485.4 million years ago. It succeeds the Miaolingian series of the Cambrian and precedes the Lower Ordovician Tremadocian Stage. It is subdivided into three stages: the Paibian, Jiangshanian and the unnamed 10th stage of the Cambrian. [5]

Contents

History and naming

The Furongian was also known as the Cambrian Series 4, and the name replaced the older term Upper Cambrian and equivalent to the local term Hunanian. The present name was ratified by the International Commission on Stratigraphy in 2003. Fúróng (芙蓉) means 'lotus' in Mandarin and refers to Hunan which is known as the "lotus state". [3]

Definition

The lower boundary is defined in the same way as the GSSP of the Paibian Stage. Both begin with the first appearance of the trilobite Glyptagnostus reticulatus around 497 million years ago. [6] The upper boundary is the lower boundary and GSSP of the Tremadocian Stage which is the first appearance of the conodont Iapetognathus fluctivagus around 485.4 million years ago. [7]

Subdivisions

The following table shows the subdivisions of the Furongian series/epoch: [5]

SeriesStageAge (Ma)
Lower Ordovician
Floian 477.7
Tremadocian 485.4
Furongian
Stage 10 489.5
Jiangshanian 494
Paibian 497
Miaolingian
Guzhangian 500.5
Drumian 504.5
Wuliuan 509

Biostratigraphy

The base of two of three stages of the Furongian are defined as the first appearance of a trilobite. The base of the Paibian is the first appearance of Glyptagnostus reticulatus and the base of the Jiangshanian is the first appearance of Agnostotes orientalis . [3] [8] The still unnamed Cambrian Stage 10 might be defined as the first appearance of Lotagnostus americanus or the conodont Eoconodontus notchpeakensis . [9]

The Furongian can be divided into a number of trilobite zones:

SeriesStageTrilobite zoneTrilobite GSSP
Furongian Stage 10 Saukia zone (upper part), Eurekia apopsis zone, Tangshanaspis Zone, Parakoldinioidia zone, Symphysurina zone [9] Lotagnostus americanus (undecided)
Jiangshanian Ellipsocephaloides zone, Saukia zone (lower part) [9] Agnostotes orientalis
Paibian  ? (?) Glyptagnostus reticulatus
Aphelaspis Zone [10]

Major events

At the beginning of the Furongian epoch, the Guzhangian–Paibian extinction ended. Species diversity, which had decreased by 45%, returned to its previous level at the very beginning of the Jiangshanian age. The ensuing Jiangshanian extinction reduced species diversity by 55.2% and was followed by an interval of relatively small fluctuations in species richness, which ended shortly after the beginning of the Ordovician. [11]

Steptoean positive carbon isotope excursion (SPICE) occurred in close proximity in time to the Miaolingian–Furongian boundary (and, accordingly, the Guzhangian–Paibian boundary). [12] This event is recorded on almost all Cambrian paleocontinents, but its exact causes are not fully understood. It is assumed that it may be associated with the Sauk megasequence, which in turn is associated with sea level changes; decrease in oxygen or occurrence of euxinic conditions in ocean waters; or the trilobite biomere turnover. [12]

From the Furongian to the Early Ordovician, around 495-470 Ma, the mantle plume activity, known as the Ollo de Sapo magmatic event, occurred on the North-Western territory of the Gondwana which is now the Iberian Peninsula. [13]

Paleontology

Researchers have been noted that the significant macroscopic soft-bodied animals that lived between the Cambrian Explosion and the Great Ordovician Biodiversification Event were not discovered. [14] In 2019, this time interval was named the Furongian Biodiversity Gap by Harper et al. This gap has been characterized as probably caused by lack of rocks, environmental events or a specific palaeogeography and extreme climates of the late Cambrian. However, a review of the literature and locations with Cambrian deposits showed that the gap is caused by the insufficient presence of Furongian deposits in sufficiently studied areas, as well as the lack of attention to fossils of this interregnum. [15] Later discoveries of the Furongian deposits in South China have allowed for a better understanding of the biostratigraphy and fluctuations in species diversity of this epoch. [11]

8502 specimens of trilobite-agnostoid fauna have been collected from the Furongian strata of the Alum Shale Formation of Bornholm, Denmark. Described gerena include Ctenopyge , Eurycare , Leptoplastus , Olenus , Parabolina , Peltura , Protopeltura , Sphaerophthalmus , Lotagnostus and Triangulopyge . [16] Benthic graptolites, including genera Rhabdopleura , Dendrograptus , Callograptus and Siberiograptus , were found in the Furongian sediments of South China. [17]

Related Research Articles

<span class="mw-page-title-main">Tremadocian</span> Lowest stage of Ordovician

The Tremadocian is the lowest stage of Ordovician. Together with the later Floian Stage it forms the Lower Ordovician Epoch. The Tremadocian lasted from 485.4 to 477.7 million years ago. The base of the Tremadocian is defined as the first appearance of the conodont species Iapetognathus fluctivagus at the Global Boundary Stratotype Section and Point (GSSP) section on Newfoundland.

Paibi, a village in Paibi Township, Huayuan County, Xiangxi Tujia and Miao Autonomous Prefecture Hunan, China, is the location of the Global Boundary Stratotype Section and Point (GSSP) which marks the boundary between the third and Furongian epochs of the Cambrian Period on the geologic time scale. Paibi was selected over the Kyrshabakty River section, Malyi Karatau, Kazakhstan, and the GSSP was ratified by the International Union of Geological Sciences in late 2003. It established the first formally agreed upon subdivision of the Cambrian. The village gives its name to the Paibian Age in the Cambrian Period.

The Paibian is the lowest stage of Furongian series of the Cambrian. It follows the Guzhangian and is succeeded by the Jiangshanian Stage. The base is defined as the first appearance of the trilobite Glyptagnostus reticulatus around 497 million years ago. The top, or the base of the Jiangshanian is defined as the first appearance of the trilobite Agnostotes orientalis around 494 million years ago.

The Floian is the second stage of the Ordovician Period. It succeeds the Tremadocian with which it forms the Lower Ordovician epoch. It precedes the Dapingian Stage of the Middle Ordovician. The Floian extended from 477.7 to 470 million years ago. The lower boundary is defined as the first appearance of the graptolite species Tetragraptus approximatus.

Lotagnostus is a genus of very small trilobites in the order Agnostida, which lived on the outer continental shelves worldwide, during the late Upper Cambrian. It was described by Whitehouse in 1936, and the type species is Lotagnostus trisectus, which was originally described as a species of Agnostus by Salter in 1864.

<span class="mw-page-title-main">Terreneuvian</span> First epoch of the Cambrian Period

The Terreneuvian is the lowermost and oldest series of the Cambrian geological system. Its base is defined by the first appearance datum of the trace fossil Treptichnus pedum around 538.8 million years ago. Its top is defined as the first appearance of trilobites in the stratigraphic record around 521 million years ago. This series' name was formally accepted by the International Commission on Stratigraphy in 2007.

Stage 2 of the Cambrian is the unnamed upper stage of the Terreneuvian Series. It lies atop the Fortunian and below Stage 3 of the Cambrian. It is commonly referred to as the Tommotian, after the Cambrian stratigraphy of Siberia. Neither the upper nor lower boundary has yet been defined by the International Commission on Stratigraphy. The preferred definitions for the lower boundary are the first appearance of the molluscs Watsonella crosbyi or Aldanella attleborensis around 529 million years ago. The correlation between the lowest occurrences of A. attleborensis and W. crosbyi with the Zhujiaqing positive carbon isotope excursion (ZHUCE) has led to the conclusion that the combination of these two markers are a reliable indicator of the boundary between the Fortunian and Stage 2. The proposed upper boundary might be the first appearance of trilobites around 521 million years ago.

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 which is estimated to be 494 million years ago. The Jiangshanian lasted until approximately 489.5 million years ago.

The Guzhangian is an uppermost stage of the Miaolingian Series of the Cambrian. It follows the Drumian Stage and precedes the Paibian Stage of the Furongian Series. The base is defined as the first appearance of the trilobite Lejopyge laevigata around 500.5 million years ago. The Guzhangian-Paibian boundary is marked by the first appearance of the trilobite Glyptagnostus reticulatus around 497 million years ago.

The Drumian is a stage of the Miaolingian Series of the Cambrian. It succeeds the Wuliuan and precedes the Guzhangian. The base is defined as the first appearance of the trilobite Ptychagnostus atavus around 504.5 million years ago. The top is defined as the first appearance of another trilobite Lejopyge laevigata around 500.5 million years ago.

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. 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 504.5 million years ago.

Stage 10 of the Cambrian is the still unnamed third and final stage of the Furongian series. It follows the Jiangshanian and precedes the Ordovician Tremadocian Stage. The proposed lower boundary is the first appearance of the trilobite Lotagnostus americanus around 489.5 million years ago, but other fossils are also being discussed. The upper boundary is defined as the appearance of the conodont Iapetognathus fluctivagus which marks the beginning of the Tremadocian and is radiometrically dated as 485.4 million years ago.

The Miaolingian is the third Series of the Cambrian Period, and was formally named in 2018. It lasted from about 509 to 497 million years ago and is divided in ascending order into 3 stages: the Wuliuan, Drumian, and Guzhangian. The Miaolingian is preceded by the unnamed Cambrian Series 2 and succeeded by the Furongian series.

<i>Glyptagnostus reticulatus</i> Extinct species of trilobite

Glyptagnostus reticulatus is a species of agnostid trilobite belonging to the genus Glyptagnostus. It existed during the Paibian Age of the Cambrian. It has a cosmopolitan distribution and is an important index fossil in biostratigraphy. It was characterized by an unusual net-like pattern of furrows on both the cephalon and the pygidium.

Cambrian Stage 4 is the still unnamed fourth stage of the Cambrian and the upper stage of Cambrian Series 2. It follows Cambrian Stage 3 and lies below the Wuliuan. The lower boundary has not been formally defined by the International Commission on Stratigraphy. One proposal is the first appearance of two trilobite genera, Olenellus or Redlichia. Another proposal is the first appearance of the trilobite species Arthricocephalus chauveaui. Both proposals will set the lower boundary close to 514 million years ago. The upper boundary corresponds to the beginning of the Wuliuan.

Agnostotes orientalis is a species of agnostid trilobite belonging to the genus Agnostotes. It existed during the Jiangshanian Age of the Cambrian. It is an important index fossil in biostratigraphy.

Cambrian Series 2 is the unnamed 2nd series of the Cambrian. It lies above the Terreneuvian series and below the Miaolingian. Series 2 has not been formally defined by the International Commission on Stratigraphy, lacking a precise lower boundary and subdivision into stages. The proposed lower boundary is the first appearance of trilobites which is estimated to be around 521 million years ago.

Westergaardodina is a species-rich genus of spine, U or W-shaped paraconodont known from Middle Cambrian to Lower Ordovician strata.

Conodonts are an extinct class of animals whose feeding apparatuses called teeth or elements are common microfossils found in strata dating from the Stage 10 of the Furongian, the fourth and final series of the Cambrian, to the Rhaetian stage of the Late Triassic. These elements can be used alternatively to or in correlation with other types of fossils in the subfield of the stratigraphy named biostratigraphy.

References

  1. ↑ "Chart/Time Scale". stratigraphy.org. International Commission on Stratigraphy.
  2. ↑ Shanchi, Peng; Babcock, Loren; Robinson, Richard; Huanling, Lin; Rees, Margaret; Saltzman, Matthew. "PROPOSED GLOBAL STANDARD STRATOTYPE-SECTION AND POINT FOR THE PAIBIAN STAGE AND FURONGIAN SERIES (UPPER CAMBRIAN)" (PDF). International Subcomission on Cambrian Stratigraphy. Archived (PDF) from the original on 2015-07-25. Retrieved 2024-04-14.
  3. 1 2 3 Peng, S. C.; Babcock, L. E.; Robison, R. A.; Lin, H. L.; Rees, M. N.; Saltzman, M. R. (2004). "Global Standard Stratotype-Section and Point (GSSP) of the Furongian Series and Paibian Stage (Cambrian)" (PDF). Lethaia. 37 (4): 365–379. doi:10.1080/00241160410002081. Archived (PDF) from the original on 2017-10-08. Retrieved 2024-04-14.
  4. ↑ Cooper, Roger; Nowlan, Godfrey; Williams, S. H. (March 2001). "Global Stratotype Section and Point for base of the Ordovician System" (PDF). Episodes. 24 (1): 19–28. doi: 10.18814/epiiugs/2001/v24i1/005 . Archived (PDF) from the original on 2024-03-25. Retrieved 2024-04-14.
  5. 1 2 "GSSP Table - Paleozoic Era". Archived from the original on 2023-10-08.
  6. ↑ "GSSP for the Paibian". Archived from the original on 2022-05-26. Retrieved 2024-04-14.
  7. ↑ "GSSP for the Cambrian - Ordovician Boundary". Archived from the original on 2016-03-03. Retrieved 2024-04-14.
  8. ↑ "GSSP for Jiangshanian". Archived from the original on 2023-01-24. Retrieved 2024-04-14.
  9. 1 2 3 Landing, E.; Westrop, S.R.; Adrain, J.M. (19 September 2011). "The Lawsonian Stage - the Eoconodontus notchpeakensis FAD and HERB carbon isotope excursion define a globally correlatable terminal Cambrian stage" (PDF). Bulletin of Geosciences: 621–640. doi: 10.3140/bull.geosci.1251 . Archived from the original (PDF) on 2023-08-29.
  10. ↑ David R. Schwimmer, William M. Montante. "An Aphelaspis zone (Upper Cambrian, paibian) trilobite faunule in the central conasauga River Valley, North Georgia, USA". Southeastern Geology. 49 (1): 31–41. Archived from the original on 2023-05-07.
  11. 1 2 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. doi:10.1016/j.palaeo.2023.111492.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  12. 1 2 Guangying Ren, Mikaela A. Pulsipher, James D. Schiffbauer, Jin-Liang Yuan, Ying Guo, Chao Chang, Fanwei Meng, Yan Zhao, Jian Gao (2021). "A contiguous record of the SPICE event, sea‐level change and the first appearance of Fenghuangella laevis in Shandong Province, North China". Lethaia. 54 (5): 1—12. doi:10.1111/let.12425.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  13. ↑ Josep Maria Casas, J. Brendan Murphy, Teresa Sanchez-Garcia, Jacques de Poulpiquet, José-Javier Alvaro, A. Díez-Montes, Joan Guimerà (2023). "Does the Ollo de Sapo magmatic event support Furongian-Tremadocian mantle plume activity fringing NW Gondwana?". International Geology Review. doi:10.1080/00206814.2023.2263787.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  14. ↑ Rudy Lerosey-Aubril, Stacey Gibb, John Paterson, Brian D. E. Chatterton (2016). "Late Cambrian (Furongian) exceptional fossils from McKay Group of British Columbia, Canada". Conference: Palaeontology Down Under 2. Adelaide, Australia.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  15. ↑ David A.T. Harper, Borja Cascales-Miñana, Yuan-Dong Zhang, Timothy Topper, Thomas Servais, Per Ahlberg (2019). "The Furongian (late Cambrian) Biodiversity Gap: Real or apparent". Palaeoworld. 28 (1–2): 4—12. doi:10.1016/j.palwor.2019.01.007.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  16. ↑ Arne Thorshøj Nielsen, Line Frigaard Andersen (2021). "Furongian (upper Cambrian) trilobites and agnostoids from the Alum Shale Formation of Bornholm, Denmark: revised taxonomy and biostratigraphy" (PDF). Bulletin of the Geological Society of Denmark. 69: 123–213. doi:10.37570/bgsd-2021-69-08. ISSN   2245-7070. Archived (PDF) from the original on 2023-10-26.
  17. ↑ Jörg Maletz, Xuejian Zhu, Yuan-Dong Zhang (2022). "Graptolithina from the Guole Biota (Furongian, upper Cambrian) of South China". Palaeoworld. 31 (8): 582—590. doi:10.1016/j.palwor.2022.03.002.{{cite journal}}: CS1 maint: multiple names: authors list (link)


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