Wenlock Epoch

Wenlock
Wenlock
Chronology
←	Lau event
←	Mulde event
←	Ireviken event
	Subdivision of the Silurian according to the ICS, as of 2021.; Vertical axis scale: millions of years ago.;
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°34′52″N 2°38′20″W / 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°21′33″N 2°46′38″W / 52.3592°N 2.7772°W
Upper GSSP ratified	1980

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.^[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.
^ "Chart/Time Scale". www.stratigraphy.org. International Commission on Stratigraphy.
^ ^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.

[Jeppsson2007-1] 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.

[Munnecke2003-2] 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.

[3] "Chart/Time Scale". www.stratigraphy.org. International Commission on Stratigraphy.

[silurianState-4] Holland, C. (1982). "The State of Silurian Stratigraphy" (PDF). Episodes. 1982: 21–23. Retrieved 11 December 2020.

[Stratchart_2013/01-5] "International Chronostratigraphic Chart 2013/01" (PDF). International Commission on Stratigraphy. Retrieved 10 July 2013.

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