Back التريمادوشي Arabic Тремадокий Bulgarian Tremadocium German Tremadociense Spanish Tremadoci lade ET ترمادوسین FA Trémadocien French Tremadociano Italian トレマドキアン Japanese Tremadocien Dutch
| Tremadocian | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| Chronology | |||||||||||
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| Etymology | |||||||||||
| Name formality | Formal | ||||||||||
| Usage information | |||||||||||
| Celestial body | Earth | ||||||||||
| Regional usage | Global (ICS) | ||||||||||
| Time scale(s) used | ICS Time Scale | ||||||||||
| Definition | |||||||||||
| Chronological unit | Age | ||||||||||
| Stratigraphic unit | Stage | ||||||||||
| Time span formality | Formal | ||||||||||
| Lower boundary definition | FAD of the Conodont Iapetognathus fluctivagus. | ||||||||||
| Lower boundary GSSP | Greenpoint section, Green Point, Newfoundland, Canada 49°40′58″N 57°57′55″W / 49.6829°N 57.9653°W | ||||||||||
| Lower GSSP ratified | 2000[5] | ||||||||||
| Upper boundary definition | FAD of the Graptolite Tetragraptus approximatus | ||||||||||
| Upper boundary GSSP | Diabasbrottet quarry, Västergötland, Sweden 58°21′32″N 12°30′09″E / 58.3589°N 12.5024°E | ||||||||||
| Upper GSSP ratified | 2002[6] | ||||||||||
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.[7]
- ^ 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.
- ^ 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.
- ^ 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
- ^ "Chart/Time Scale". www.stratigraphy.org. International Commission on Stratigraphy.
- ^ 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. Retrieved 6 December 2020.
- ^ 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. doi:10.18814/epiiugs/2004/v27i4/005. Retrieved 13 December 2020.
- ^ "GSSP Table - Paleozoic Era". Geologic TimeScale Foundation. Retrieved 24 November 2012.