Wenlock Epoch

Wenlock
433.4 ± 0.8 – 427.4 ± 0.5 Ma
Map of Earth as it appeared 430 million years ago during the Wenlock epoch, Homerian stage[citation needed]
Chronology
Etymology
Name formalityFormal
Name ratified1980[4]
Usage information
Celestial bodyEarth
Regional usageGlobal (ICS)
Time scale(s) usedICS Time Scale
Definition
Chronological unitEpoch
Stratigraphic unitSeries
Time span formalityFormal
Lower boundary definitionImprecise. Currently placed between acritarch biozone 5 and last appearance of Pterospathodus amorphognathoides. See Llandovery for more info.
Lower boundary definition candidatesA conodont boundary (Ireviken datum 2) which is close to the murchisoni graptolite biozone.
Lower boundary GSSP candidate section(s)None
Lower boundary GSSPHughley Brook, Apedale, U.K.
52°34′52″N 2°38′20″W / 52.5811°N 2.6389°W / 52.5811; -2.6389
Lower GSSP ratified1980[4]
Upper boundary definitionFAD of the Graptolite Saetograptus (Colonograptus) varians
Upper boundary GSSPPitch Coppice, Ludlow, U.K.
52°21′33″N 2°46′38″W / 52.3592°N 2.7772°W / 52.3592; -2.7772
Upper GSSP ratified1980[4]

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]

  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.
  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.
  4. ^ a b c Holland, C. (1982). "The State of Silurian Stratigraphy" (PDF). Episodes. 1982: 21–23. Retrieved 11 December 2020.
  5. ^ "International Chronostratigraphic Chart 2013/01" (PDF). International Commission on Stratigraphy. Retrieved 10 July 2013.