View source for Earth:Epoch (geology)

{{short description|Subdivision of geological time; shorter than a period and longer than an age}}

In [[Physics:Geochronology|geochronology]], an '''epoch''' is a subdivision of the geologic timescale that is longer than an [[Earth:Age (geology)|age]] but shorter than a period. The current epoch is the [[Earth:Holocene|Holocene]] Epoch of the [[Earth:Quaternary|Quaternary]] Period. Rock layers deposited during an epoch are called a [[Earth:Series (stratigraphy)|series]]. Series are subdivisions of the [[Earth:Stratigraphic column|stratigraphic column]] that, like epochs, are subdivisions of the geologic timescale. Like other geochronological divisions, epochs are normally separated by significant changes in the rock layers to which they correspond.

Epochs are most commonly used for the younger [[Earth:Cenozoic|Cenozoic]] [[Earth:Era (geology)|Era]], where a greater collection of [[Biology:Fossil|fossil]]s has been found and paleontologists have more detailed knowledge of the events that occurred during those times. They are less commonly referred to for the other eras and [[Earth:Eon (geology)|eons]], since less fossil evidence exists that allows us to form a clearer view of those time periods.

==List of epochs (series) in the Phanerozoic eon==
{{main|Earth:Phanerozoic}}
List is ordered from youngest to oldest and subdivided based on [[Earth:Era (geology)|era]] and period. Certain periods, notably those in the Mesozoic are divided into Early, Middle and Late epochs, with the corresponding stratigraphic 'series' named as Lower, Middle and Upper.

[[Earth:Cenozoic|Cenozoic]] Era

*[[Earth:Quaternary|Quaternary]] Period
**Anthropocene Epoch (proposed)
**[[Earth:Holocene|Holocene]] Epoch
**[[Earth:Pleistocene|Pleistocene]] Epoch
*[[Earth:Neogene|Neogene]] Period
**Pliocene Epoch
**Miocene Epoch
*[[Earth:Paleogene|Paleogene]] Period
**[[Earth:Oligocene|Oligocene]] Epoch
**[[Earth:Eocene|Eocene]] Epoch
**[[Earth:Paleocene|Paleocene]] Epoch

[[Earth:Mesozoic|Mesozoic]] Era
*[[Earth:Cretaceous|Cretaceous]] Period
**[[Earth:Late Cretaceous|Late (Upper)]] Epoch
**[[Earth:Early Cretaceous|Early (Lower)]] Epoch
*[[Earth:Jurassic|Jurassic]] Period
**Late (Upper) Epoch
**Middle Epoch
**Early (Lower) Epoch
*[[Earth:Triassic|Triassic]] Period
**[[Earth:Late Triassic|Late (Upper)]] Epoch
**[[Earth:Middle Triassic|Middle]] Epoch
**[[Earth:Early Triassic|Early (Lower)]] Epoch

[[Earth:Paleozoic|Paleozoic]] Era

*[[Earth:Permian|Permian]] Period
**[[Earth:Lopingian|Lopingian]] Epoch
**[[Earth:Guadalupian|Guadalupian]] Epoch
**[[Earth:Cisuralian|Cisuralian]] Epoch
*[[Earth:Carboniferous|Carboniferous]] Period
**Pennsylvanian Epoch*
**Mississippian  Epoch*
*[[Earth:Devonian|Devonian]] Period Epoch
**Late (Upper) Epoch
**Middle Epoch
**Early (Lower) Epoch
*[[Earth:Silurian|Silurian]] Period
**[[Earth:Pridoli epoch|Pridoli]] Epoch
**[[Earth:Ludlow Group|Ludlow]] Epoch
**Wenlock Epoch
**[[Earth:Llandovery Group|Llandovery]]  Epoch
*[[Earth:Ordovician|Ordovician]] Period
**Late (Upper) Epoch
**Middle Epoch
**Early (Lower) Epoch
*[[Earth:Cambrian|Cambrian]] Period
**[[Earth:Furongian|Late (Upper)/Furongian]] Epoch
**Middle Epoch
**Early (Lower) Epoch

(Note that there are differences in the rank traditionally accorded to divisions of the Carboniferous between Europe and North America.)

=== Geological hierarchy of chronological periodization ===
[[Physics:Geochronology|Geochronology]]: From largest to smallest:
# Supereon
# [[Earth:Eon (geology)|Eon]]
# [[Earth:Era (geology)|Era]]
# Period
# [[Earth:Epoch (geology)|Epoch]]
# [[Earth:Age (geology)|Age]]
# [[Earth:Polarity chron|Chron]]

==References==
{{reflist}}
* {{cite book |last1=Gradstein |first1=F.M. |last2=Ogg |first2=J.G. |last3=Smith |first3=A.G. |title=A geologic time scale 2004 |date=2004 |publisher=Cambridge University Press |location=Cambridge, UK |isbn=9780521786737}}

{{Clear}}
{{Geological history|c}}

[[Category:Geochronology]]
[[Category:Geologic time scales]]

{{Sourceattribution|Epoch (geology)|1}}