Floian

Last updated
Floian
477.7 ± 1.4 – 470.0 ± 1.4 Ma
Chronology
Etymology
Name formalityFormal
Usage information
Celestial body Earth
Regional usageGlobal (ICS)
Time scale(s) usedICS Time Scale
Definition
Chronological unit Age
Stratigraphic unit Stage
Time span formalityFormal
Lower boundary definition FAD of the Graptolite Tetragraptus approximatus
Lower boundary GSSP Diabasbrottet quarry, Västergötland, Sweden
58°21′32″N12°30′09″E / 58.3589°N 12.5024°E / 58.3589; 12.5024
Lower GSSP ratified2002 [5]
Upper boundary definitionFAD of the Conodont Baltoniodus triangularis
Upper boundary GSSPHuanghuachang section, Huanghuachang, Yichang, China
30°51′38″N110°22′26″E / 30.8605°N 110.3740°E / 30.8605; 110.3740
Upper GSSP ratified2007 [6]

The Floian is the second stage of the Ordovician Period. It succeeds the Tremadocian with which it forms the Lower Ordovician series. It precedes the Dapingian Stage of the Middle Ordovician. The Floian extended from 477.7 to 470 million years ago. [7] The lower boundary is defined as the first appearance of the graptolite species Tetragraptus approximatus . [8]

Contents

History and naming

The base of this stage was ratified by the International Commission on Stratigraphy (ICS) in 2002. The Floian Stage is named after Flo, a village in Västergötland, southern Sweden. The name "Floan" was proposed in 2004, [9] but the ICS adapted Floian as the official name of the stage. [10]

GSSP

The GSSP of the Floian is the lower Tøyen Shale in Diabasbrottet Quarry ( 58°21′32″N12°30′09″E / 58.3589°N 12.5024°E / 58.3589; 12.5024 ) which is an outcrop of a shale-dominated stratigraphic succession. The lower boundary of the Floian is defined as the first appearance of Tetragraptus approximatus which is about 2.1 above the Cambrian strata. [9] Radiometric dating has set the Tremadocian-Floian boundary at 477.7 million years ago. [7]

The upper boundary which is also the base of the Dapingian stage is defined as the first appearance of the conodont species Baltoniodus triangularis at the GSSP in the Huanghuachang Section, Hubei Province, China. [11]

Regional stages

Partial analogues of Floian stage in Baltoscandia are Hunneberg stage (lower) and Billingen stage (upper). [12] [13] On the Siberian Platform, Ugorian stage corresponds to Floian. [14]

Major events

The global Billingen Transgressive Event occurred in the Early Floian age. Black graptolitic argillites of Gorny Altai as well as conglomerates and gritstones of Salair, Russia, possibly correlates with this event. [15]

Paleontology

Discovered in the Floian strata of Newfoundland, coral-like fossils of Reptamsassia divergens and Reptamsassia minuta are the oldest example of symbiotic intergrowth of modular species. This allows to judge the level of development of reef ecosystems of the Early Ordovician. [16]

Conodonts Serratognathus , Prioniodus and Oepikodus were distributed in Kazakhstan, Korea, China, Indochina and Australasia during the Floian age. Two species of Paroistodus are known from the Floian deposits of Baltoscandia and South China. [17]

Several thousand chemically isolated graptolite specimens including genera Baltograptus and Pseudophyllograptus were collected from the upper Floian sediments of Skattungbyn, Dalarna, central Sweden. Presented mostly by juveniles and isolated siculae, these graptolites inhabited primarily in shallow water environment. [18]

Trilobites of the genera Tsaidamaspis , Zhiyia and Liexiaspis were found in the Floian part of the Duoquanshan Formation, northwest China. [19]

Falloaster anquiroisitus , an asterozoan of problematic classification, is known from the Floian Garden City Formation of Idaho, USA. [20]

Related Research Articles

<span class="mw-page-title-main">Ordovician</span> Second period of the Paleozoic Era 485–444 million years ago

The Ordovician is a geologic period and system, the second of six periods of the Paleozoic Era. The Ordovician spans 41.6 million years from the end of the Cambrian Period 485.4 Ma to the start of the Silurian Period 443.8 Ma.

The Early Ordovician is the first epoch of the Ordovician period, corresponding to the Lower Ordovician series of the Ordovician system. It began after the Age 10 of the Furongian epoch of the Cambrian and lasted from 485.4 ± 1.9 to 470 ± 1.4 million years ago, until the Dapingian age of the Middle Ordovician. It includes Tremadocian and Floian ages.

First appearance datum (FAD) is a term used by geologists and paleontologists to designate the first appearance of a species in the geologic record. FADs are determined by identifying the geologically oldest fossil discovered, to date, of a particular species. A related term is last appearance datum (LAD), the last appearance of a species in the geologic record.

<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.

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.

The Darriwilian is the upper stage of the Middle Ordovician. It is preceded by the Dapingian and succeeded by the Upper Ordovician Sandbian Stage. The lower boundary of the Darriwilian is defined as the first appearance of the graptolite species Undulograptus austrodentatus around 467.3 million years ago. It lasted for about 8.9 million years until the beginning of the Sandbian around 458.4 million years ago. This stage of the Ordovician was marked by the beginning of the Andean-Saharan glaciation.

The Diabasbrottet Quarry, located on Mt. Hunneberg, Västergötland, Sweden, is the location of the Global Boundary Stratotype Section and Point (GSSP) which marks the lower boundary of the Floian stage of the Lower Ordovician.

In the geological timescale, the Llandovery Epoch occurred at the beginning of the Silurian Period. The Llandoverian Epoch follows the massive Ordovician-Silurian extinction events, which led to a large decrease in biodiversity and an opening up of ecosystems.

<span class="mw-page-title-main">Katian</span>

The Katian is the second stage of the Upper Ordovician. It is preceded by the Sandbian and succeeded by the Hirnantian Stage. The Katian began 453 million years ago and lasted for about 7.8 million years until the beginning of the Hirnantian 445.2 million years ago. During the Katian the climate cooled which started the Late Ordovician glaciation.

The Sandbian is the first stage of the Upper Ordovician. It follows the Darriwilian and is succeeded by the Katian. Its lower boundary is defined as the first appearance datum of the graptolite species Nemagraptus gracilis around 458.4 million years ago. The Sandbian lasted for about 5.4 million years until the beginning of the Katian around 453 million years ago.

The Dapingian is the third stage of the Ordovician system and the first stage of the Middle Ordovician series. It is preceded by the Floian and succeeded by the Darriwilian. The base of the Dapingian is defined as the first appearance of the conodont species Baltoniodus triangularis which happened about 470 million years ago. The Dapingian lasted for about 2.7 million years until about 467.3 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 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.

<span class="mw-page-title-main">Flo, Sweden</span> Historic parish (socken) in Swedish

Flo is a historic parish (socken) in the Swedish province of Västergötland. Since 1971 it has been a part of Grästorp Municipality.

Iapetognathus fluctivagus is a species of denticulate cordylodan conodonts belonging to the genus Iapetognathus. It existed during the Tremadocian Age of the Ordovician. It is an important index fossil in biostratigraphy.

<i>Tetragraptus approximatus</i> Species of marine worm-like animal

Tetragraptus approximatus is a species of dichograptid graptolite belonging to the genus Tetragraptus. It existed during the Floian Age of the Ordovician. It is an important index fossil in biostratigraphy.

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. ↑ Wellman, C.H.; Gray, J. (2000). "The microfossil record of early land plants". Phil. Trans. R. Soc. B . 355 (1398): 717–732. doi:10.1098/rstb.2000.0612. PMC   1692785 . PMID   10905606.
  2. ↑ Korochantseva, Ekaterina; Trieloff, Mario; Lorenz, Cyrill; Buykin, Alexey; Ivanova, Marina; Schwarz, Winfried; Hopp, Jens; Jessberger, Elmar (2007). "L-chondrite asteroid breakup tied to Ordovician meteorite shower by multiple isochron 40 Ar- 39 Ar dating". Meteoritics & Planetary Science. 42 (1): 113–130. Bibcode:2007M&PS...42..113K. doi:10.1111/j.1945-5100.2007.tb00221.x.
  3. ↑ Lindskog, A.; Costa, M. M.; Rasmussen, C.M.Ø.; Connelly, J. N.; Eriksson, M. E. (2017-01-24). "Refined Ordovician timescale reveals no link between asteroid breakup and biodiversification". Nature Communications. 8: 14066. doi:10.1038/ncomms14066. ISSN   2041-1723. PMC   5286199 . PMID   28117834. It has been suggested that the Middle Ordovician meteorite bombardment played a crucial role in the Great Ordovician Biodiversification Event, but this study shows that the two phenomena were unrelated
  4. ↑ "Chart/Time Scale". www.stratigraphy.org. International Commission on Stratigraphy.
  5. ↑ Bergström, M.; Löfgren, Anita; Maletz, Jörg (December 2004). "The GSSP of the Second (Upper) Stage of the Lower Ordovician Series: Diabasbrottet at Hunneberg, Province of Västergötland, Southwestern Sweden". Episodes. 27 (4): 265–272. Retrieved 13 December 2020.
  6. ↑ Chen, Xu; Bergström, Stig; Zhang, Yuan-Dong; Fan, Jun-Xuan (2009). "The base of the Middle Ordovician in China with special reference to the succession at Hengtang near Jiangshan, Zhejiang Province, southern China" (PDF). Lethaia. 42: 218–231. doi:10.1111/j.1502-3931.2008.00148.x. Archived (PDF) from the original on 2024-01-06. Retrieved 2024-04-20.
  7. 1 2 "Latest version of international chronostratigraphic chart". International Commission on Stratigraphy. Retrieved 2024-06-13.
  8. ↑ "GSSP for Floian Stage". Geologic TimeScale Foundation. Archived from the original on 2024-04-16.
  9. 1 2 Bergström, Stig M.; Anita Löfgren; Jörg Maletz (2004). "The GSSP of the Second (Upper) Stage of the Lower Ordovician Series: Diabasbrottet at Hunneberg, Province of Västergötland, Southwestern Sweden" (PDF). Episodes. 27 (4): 265–272. Archived (PDF) from the original on 2024-04-16. Retrieved 2024-04-20.
  10. ↑ Stig M. Bergström, Stanley Finney, Chen Xu, Daniel Goldman, Stephen A. Leslie (2006). "Three new Ordovician global stage names". Lethaia . 39 (4): 287–288. doi:10.1080/00241160600847439. Archived from the original on 2024-04-20.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  11. ↑ "GSSP for Dapingian Stage". Geologic TimeScale Foundation. Archived from the original on 2024-04-04.
  12. ↑ Helje Pärnaste, Viive Viira (2012). "On the lower boundary of the Floian Stage in Estonia". Estonian Journal of Earth Sciences. 61 (2): 205–209. doi:10.3176/earth.2012.4.02.
  13. ↑ "Ordovician of the Baltic". Paleobiology Database . Archived from the original on 2024-04-16. Retrieved 2024-04-20.
  14. ↑ V. E. Pavlov, Andrei Dronov, Alexander Larionov, Tatiana Yu. Tolmacheva (2022). Magnetostratigraphic Constraints on the Position of the Tremadocian–Floian Boundary at the Key Section of the Moyero River Valley (Siberian Platform) [In book: Problems of Geocosmos–2020]. Springer Nature. p. 107–114. doi:10.1007/978-3-030-91467-7. ISBN   978-3-030-91467-7. ISSN   2524-3438.{{cite book}}: CS1 maint: multiple names: authors list (link)
  15. ↑ N. V. Sennikov, O. T. Obut, E. V. Lykova, A. V. Timokhin, R. A. Khabibulina, T. A. Shcherbanenko (2021). "Event Stratigraphy and Correlation Problems of the Ordovician strata of Gorny Altai and Salair". Geodynamics & Tectonophysics (in Russian). 12 (2): 246—260. doi: 10.5800/GT-2021-12-2-0523 .{{cite journal}}: CS1 maint: multiple names: authors list (link)
  16. ↑ Dong-Jin Lee, Robert Elias, Brian R. Pratt (2022). "Reptamsassia n. gen. (Amsassiaceae n. fam.; calcareous algae) from the Lower Ordovician (Floian) of western Newfoundland, and the earliest symbiotic intergrowth of modular species". Journal of Paleontology. 96 (3): 1—14. doi:10.1017/jpa.2021.122.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  17. ↑ Yong Yi Zhen, Ian G. Percival, Yuan-Dong Zhang (2014). "Floian (Early Ordovician) conodont-based biostratigraphy and biogeography of the Australasian Superprovince". Palaeoworld. 24 (1–1): 100–109. doi:10.1016/j.palwor.2014.10.011.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  18. ↑ Jörg Maletz (2022). "Roland Skoglund's late Floian graptolites from Dalarna, central Sweden". Historical Biology. 35 (9): 1583-1604. doi:10.1080/08912963.2022.2104642.
  19. ↑ Xin Wei, Zhiqiang Zhou (2023). "Floian, Early Ordovician trilobites from the Olongbluk Terrane, northwest China". Acta Palaeontologica Polonica. 68. doi: 10.4202/app.01102.2023 .
  20. ↑ Daniel B. Blake, Forest J. Gahn, Thomas E. Guensburg (2019). "An Early Ordovician (Floian) asterozoan (Echinodermata) of problematic class-level affinities". Journal of Paleontology. 94 (2): 1-8. doi:10.1017/jpa.2019.82.{{cite journal}}: CS1 maint: multiple names: authors list (link)
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