Wenlock Epoch
![]() | A request that this article title be changed to Wenlock (geology) is under discussion. Please do not move this article until the discussion is closed. |
Wenlock | |
---|---|
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 432.9 and 426.7 million years ago.[5]
Naming and history
The Wenlock is named after Wenlock Edge, an outcrop of rocks near the town of Much Wenlock in Shropshire (West Midlands, United Kingdom).[6] The name was first used in the term "Wenlock and Dudley rocks" by Roderick Murchison in 1834 to refer to the limestones and underlying shales that underlay what he termed the "Ludlow rocks".[7] He later modified this term to simply the "Wenlock rocks" in his book, The Silurian System in 1839.[8]
Definition and subdivision
The Wenlock's beginning is defined by the lower boundary (or
The Wenlock is divided into the older Sheinwoodian and the younger Homerian stage. The Sheinwoodian lasted from 432.9 to 430.6 million years ago. The Homerian lasted from 430.6 to 426.7 million years ago.[5]
References
- .
- .
- ^ "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.
- ^ a b "International Chronostratigraphic Chart 2013/01" (PDF). International Commission on Stratigraphy. Retrieved 10 July 2013.
- ISBN 9780521786737.
- ^ Murchison R.I. (1833–1834). "On the Structure and Classification of the Transition Rocks of Shropshire, Herefordshire and part of Wales and on the Lines of Disturbance which have affected that Series of Deposits, including the Valley of Elevation of Woolhope". Proceedings of the Geological Society of London. 2 (33): 14.
- ^ Murchison R.I. (1839). The Silurian System. Murray. p. 208.
- ISBN 978-0-444-59425-9.