Wenlock Epoch
The Wenlock (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.
| Wenlock | |||||||||||||
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| Chronology | |||||||||||||
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| Etymology | |||||||||||||
| Name formality | Formal | ||||||||||||
| Name ratified | 1980 | ||||||||||||
| 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. 52.5811°N 2.6389°W | ||||||||||||
| Lower GSSP ratified | 1980 | ||||||||||||
| Upper boundary definition | FAD of the Graptolite Saetograptus (Colonograptus) varians | ||||||||||||
| Upper boundary GSSP | Pitch Coppice, Ludlow, U.K. 52.3592°N 2.7772°W | ||||||||||||
| Upper GSSP ratified | 1980 | ||||||||||||
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