Floian

Floian
477.7 ± 1.4 – 470.0 ± 1.4 Ma
Chronology
Etymology
Name formalityFormal
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 Graptolite Tetragraptus approximatus
Lower boundary GSSPDiabasbrottet quarry, Västergötland, Sweden
58°21′32″N 12°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″N 110°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]

  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. ^ "International Chronostratigraphic Chart" (PDF). International Commission on Stratigraphy. September 2023. Retrieved November 10, 2024.
  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. ^ "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.