{{short description|2nd Series (Epoch) of the Silurian}} {{Infobox geologic timespan | name = Wenlock | color = Wenlock | time_start = 432.9 | time_start_uncertainty = 1.2 | time_end = 426.7 | time_end_uncertainty = 1.5 | image_map = Mollweide Paleographic Map of Earth, 430 Ma (Homerian Age).png | caption_map = A map of Earth as it appeared 430 million years ago during the Wenlock Epoch, Homerian Age | image_outcrop = | caption_outcrop = | image_art = | caption_art = <!--Chronology--> | timeline = Silurian <!--Etymology--> | name_formality = Formal | name_accept_date = 1980<ref name="silurianState">{{cite journal |last1=Holland |first1=C. |title=The State of Silurian Stratigraphy |journal=Episodes |date=1982 |volume=1982 |pages=21-23 |url=https://stratigraphy.org/gssps/files/sheinwoodian-ludfordian.pdf |access-date=11 December 2020}}</ref> | alternate_spellings = | synonym1 = | synonym1_coined = | synonym2 = | synonym2_coined = | synonym3 = | synonym3_coined = | nicknames = | former_names = | proposed_names = <!--Usage Information--> | celestial_body = earth | usage = Global (ICS) | timescales_used = ICS Time Scale | formerly_used_by = | not_used_by = <!--Definition--> | chrono_unit = Epoch | strat_unit = Series | proposed_by = | timespan_formality = Formal | lower_boundary_def = Imprecise. Currently placed between acritarch biozone 5 and last appearance of ''Pterospathodus amorphognathoides''. See Llandovery for more info. | lower_gssp_candidates = None | lower_def_candidates = A conodont boundary (Ireviken datum 2) which is close to the ''murchisoni'' graptolite biozone. | lower_gssp_location = Hughley Brook, Apedale, U.K. | lower_gssp_coords = {{Coord|52.5811|N|2.6389|W|display=inline}} | lower_gssp_accept_date = 1980<ref name="silurianState"/> | upper_boundary_def = FAD of the Graptolite ''Saetograptus (Colonograptus) varians'' | upper_gssp_location = Pitch Coppice, Ludlow, U.K. | upper_gssp_coords = {{Coord|52.3592|N|2.7772|W|display=inline}} | upper_gssp_accept_date = 1980<ref name="silurianState"/> <!--Atmospheric and Climatic Data--> | o2 = | co2 = | temp = | sea_level = }}
The '''Wenlock Epoch''' (sometimes referred to as the '''Wenlockian''') or Mid-Early Silurian 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 {{Period start|Wenlock}} and {{Period start|Ludlow}} million years ago.<ref name="Stratchart 2013/01">{{cite web|title=International Chronostratigraphic Chart 2013/01|url=https://www.stratigraphy.org/ICSchart/ChronostratChart2013-01.pdf|publisher=International Commission on Stratigraphy|access-date=10 July 2013}}</ref>
== 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).<ref name="a2004">{{cite book |isbn=9780521786737|title=A Geologic Time Scale 2004|last1=Gradstein|first1=Felix M.|last2=Ogg|first2=James G.|last3=Smith|first3=Alan G.|year=2004}}</ref> 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".<ref name="Murchison_1834">{{cite journal | url=https://archive.org/details/proceedings218331838geol | title=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 | author=Murchison R.I. | journal=Proceedings of the Geological Society of London | year=1833–1834 | volume=2 | issue=33 | pages=[https://archive.org/details/proceedings218331838geol/page/14 14]}}</ref> He later modified this term to simply the "Wenlock rocks" in his book, ''The Silurian System'' in 1839.<ref name="Murchison_1839">{{cite book | url=https://books.google.com/books?id=cKlAAAAAcAAJ&q=murchison+wenlock+limestone&pg=PA209 | title=The Silurian System | publisher=Murray | author=Murchison R.I. | author-link=Roderick Murchison | year=1839 | pages=208}}</ref>
== Definition and subdivision == The Wenlock's beginning is defined by the lower boundary (or GSSP) of the Sheinwoodian. The end is defined as the base (or GSSP) of the Gorstian.<ref name=GTS2012>{{cite book|title=The Geologic Time Scale 2012|date=14 August 2012|publisher=Elsevier Science Ltd|isbn=978-0-444-59425-9}}</ref>
The Wenlock is divided into the older Sheinwoodian and the younger Homerian stage. The Sheinwoodian lasted from {{Period start|Sheinwoodian}} to {{Period start|Homerian}} million years ago. The Homerian lasted from {{Period start|Homerian}} to {{Period start|Gorstian}} million years ago.<ref name="Stratchart 2013/01" />
== References == {{Reflist}}
{{Silurian footer}} {{Geological history|p|p}}
Category:Wenlock epoch *02 Category:Geological epochs Category:Wenlock first appearances
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