Wenlock (Silurian)

Key events in the Silurian

view • discuss • 

-444 —

–

-442 —

–

-440 —

–

-438 —

–

-436 —

–

-434 —

–

-432 —

–

-430 —

–

-428 —

–

-426 —

–

-424 —

–

-422 —

–

-420 —

–

-418 —

P
a
l
e
o
z
o
i
c

Ordovician

S
i
l
u
r
i
a
n

Devonian

L
l
a
n
d
o
v
e
r
y

W
e
n
l
o
c
k

L
u
d
l
o
w

Pridoli

Rhuddanian

Aeronian

Telychian

Sheinwoodian

Homerian

Gorstian

Ludfordian

 

 

 

 

 

←

Lau event

←

Mulde event^[1]

←

Ireviken
event^[2]

Key events of the Silurian Period.
Axis scale: millions of years ago.

The Wenlock (seldomly also referred to as Wenlockian) is the second series of the Silurian. It is preceded by the Llandovery series and followed by the Ludlow. Radiometric dates constrain the Wenlockian between 433.4 ± 0.8 and 427.4 ± 0.5 million years ago.^[3]

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). 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".^[4] He later modified this term to simply the "Wenlock rocks" in his the Silurian System in 1839.^[5]

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.^[6]

The Wenlock is divided into the older Sheinwoodian and the younger Homerian stage. The Sheinwoodian lasted from 433.4 ± 0.8 to 430.5 ± 0.7 million years ago. The Homerian lasted from 430.5 ± 0.7 to 427.4 ± 0.5 million years ago.^[3]

References

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. "International Chronostratigraphic Chart 2013/01" (PDF). International Commission on Stratigraphy. Retrieved 10 July 2013.
4. 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" (PDF). Proceedings of the Geological Society 2 (33): 14.
5. Murchison R.I. (1839). The Silurian System. Murray. p. 208.
6. The Geologic Time Scale 2012. Elsevier Science Ltd. ISBN 978-0-444-59425-9.