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Wenlock Epoch
| Wenlock | |||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
.png) A map of Earth as it appeared 430 million years ago during the Wenlock Epoch, Homerian Age | |||||||||||||
| Chronology | |||||||||||||
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| Etymology | |||||||||||||
| Name formality | Formal | ||||||||||||
| Name ratified | 1980[4] | ||||||||||||
| Usage information | |||||||||||||
| Celestial body | Earth | ||||||||||||
| Regional usage | Global (ICS) | ||||||||||||
| Time scale(s) used | ICS Time Scale | ||||||||||||
| Definition | |||||||||||||
| Chronological unit | Epoch | ||||||||||||
| Stratigraphic unit | Series | ||||||||||||
| Time span formality | Formal | ||||||||||||
| Lower boundary definition | Imprecise. Currently placed between acritarch biozone 5 and last appearance of Pterospathodus amorphognathoides. See Llandovery for more info. | ||||||||||||
| Lower boundary definition candidates | A conodont boundary (Ireviken datum 2) which is close to the murchisoni graptolite biozone. | ||||||||||||
| Lower boundary GSSP candidate section(s) | None | ||||||||||||
| Lower boundary GSSP | Hughley Brook, Apedale, U.K. 52°34′52″N 2°38′20″W / 52.5811°N 2.6389°W | ||||||||||||
| Lower GSSP ratified | 1980[4] | ||||||||||||
| Upper boundary definition | FAD of the Graptolite Saetograptus (Colonograptus) varians | ||||||||||||
| Upper boundary GSSP | Pitch Coppice, Ludlow, U.K. 52°21′33″N 2°46′38″W / 52.3592°N 2.7772°W | ||||||||||||
| Upper GSSP ratified | 1980[4] | ||||||||||||
The Wenlock Epoch (sometimes referred to as the Wenlockian) is the second epoch of the Silurian. It is preceded by the Llandovery Epoch and followed by the Ludlow Epoch. Radiometric dates constrain the Wenlockian between 433.4 and 427.4 million years ago.[5]
- ^ 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.
- ^ a b c Holland, C. (1982). "The State of Silurian Stratigraphy" (PDF). Episodes. 1982: 21–23. Retrieved 11 December 2020.
- ^ "International Chronostratigraphic Chart 2013/01" (PDF). International Commission on Stratigraphy. Retrieved 10 July 2013.
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