Telychian
| Telychian | |||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
 Paleogeography of the Telychian, 435 Ma | |||||||||||||
| 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 graptolite Spirograptus guerichi | ||||||||||||
| Lower boundary GSSP | El Pintado section,
Seville, Spain 37°59′07″N 5°55′43″W / 37.9853°N 5.9285°W[4] | ||||||||||||
| Lower GSSP ratified | 2024[5][6] | ||||||||||||
| Upper boundary definition | Imprecise. Currently placed between acritarch biozone 5 and LAD of Pterospathodus amorphognathoides. See Llandovery for more info. | ||||||||||||
| Upper boundary definition candidates | A conodont boundary (Ireviken datum 2) which is close to the murchisoni graptolite biozone. | ||||||||||||
| Upper boundary GSSP candidate section(s) | None | ||||||||||||
| Upper boundary GSSP | Hughley Brook, Apedale, UK 52°34′52″N 2°38′20″W / 52.5811°N 2.6389°W | ||||||||||||
| Upper GSSP ratified | 1980[7] | ||||||||||||
In the geologic timescale, the Telychian is the third and final age of the Llandovery Epoch of the Silurian Period of the Paleozoic Era of the Phanerozoic Eon. The Telychian Age was between 438.5 ± 1.2 million years ago (Ma) and 433.4 ± 0.8 Ma. The Telychian Age succeeds the Aeronian Age and precedes the Sheinwoodian Age.[8] The name of the interval is derived from the Pen-lan-Telych Farm near Llandovery, Powys, Wales.
It ended with the Ireviken event.
Ireviken event
[edit]The Ireviken event was the first of three relatively minor extinction events (the Ireviken, Mulde, and Lau events) during the Silurian Period. It occurred at the Llandovery/Wenlock boundary (mid Silurian, 433.4 ± 0.8 million years ago). The event is best recorded at Ireviken, Gotland, where over 50% of trilobite species became extinct; 80% of the global conodont species also become extinct in this interval.
References
[edit]- ^ Jeppsson, L.; Calner, M. (2007). "The Silurian Mulde Event and a scenario for secundo—secundo events". Earth and Environmental Science Transactions of the Royal Society of Edinburgh. 93 (02): 135–154. doi:10.1017/S0263593300000377.
- ^ Munnecke, A.; Samtleben, C.; Bickert, T. (2003). "The Ireviken Event in the lower Silurian of Gotland, Sweden-relation to similar Palaeozoic and Proterozoic events". Palaeogeography, Palaeoclimatology, Palaeoecology. 195 (1): 99–124. doi:10.1016/S0031-0182(03)00304-3.
- ^ "International Chronostratigraphic Chart" (PDF). International Commission on Stratigraphy. September 2023. Retrieved December 16, 2024.
- ^ "Global Boundary Stratotype Section and Point". International Commission of Stratigraphy. Retrieved 3 August 2024.
- ^ Gutierrez-Marco, Juan Carlos (2021). "Silurian Treasures in Spanish UNESCO Global Geoparks" (PDF). Silurian Times. 29: 16–21. doi:10.13140/RG.2.2.13314.15044.
- ^ "Silurian Telychian and Aeronian stage GSSPs have been relocated". stratigraphy.org. International Commission on Stratigraphy. Retrieved 1 March 2024.
- ^ Holland, C. (1982). "The State of Silurian Stratigraphy" (PDF). Episodes. 1982: 21–23. Retrieved 11 December 2020.
- ^ Gradstein, Felix M.; Ogg, James G.; Smith, Alan G. (2004). A Geologic Time Scale 2004. ISBN 9780521786737.
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