View source for Early Devonian

{{Short description|First epoch/series of the Devonian}}
{{Infobox geologic timespan
| name                         = Early Devonian
| color                        = Early Devonian
| top_bar                      =
| time_start                   = 419.2
| time_start_uncertainty       = 3.2
| time_end                     = 393.3
| time_end_uncertainty         = 0.4
| image_map                    = Mollweide Paleographic Map of Earth, 405 Ma (Emsian Age).png
| caption_map                  = A map of Earth as it appeared 405 million years ago during the Early Devonian Epoch, Emsian Age
| image_outcrop                = Rhynie chert.jpg
| caption_outcrop              = Sample from the Lower Devonian [[Rhynie chert]]
| image_art                    = 
| caption_art                  =
<!--Chronology-->  
| timeline                     = Devonian
<!--Etymology-->
| chrono_name                  = Early Devonian
| strat_name                   = Lower Devonian
| name_formality               = Formal
| name_accept_date             =
| alternate_spellings          =
| synonym1                     =
| synonym1_coined              =
| synonym2                     =
| synonym2_coined              =
| synonym3                     =
| synonym3_coined              =
| nicknames                    =
| former_names                 =
| proposed_names               =
<!--Usage Information--> 
| celestial_body               = earth
| usage                        = Global ([[International Commission on Stratigraphy|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           = [[First appearance datum|FAD]] of the [[graptolite]] ''[[Monograptus|Monograptus uniformis]]''
| lower_gssp_location          = [[Klonk]], [[Czech Republic]]
| lower_gssp_coords            = {{Coord|49.8550|N|13.7920|E|display=inline}}
| lower_gssp_accept_date       = 1972<ref>{{cite journal |last1=Chlupáč |first1=Ivo |last2=Hladil |first2=Jindrich |title=The global stratotype section and point of the Silurian-Devonian boundary |journal=CFS Courier Forschungsinstitut Senckenberg |date=January 2000 |pages=1–8 |url=https://www.researchgate.net/publication/260135817 |access-date=7 December 2020}}</ref>
| upper_boundary_def           = [[First appearance datum|FAD]] of the [[conodont]] ''[[Polygnathus|Polygnathus costatus partitus]]''
| upper_gssp_location          = [[Wetteldorf Richtschnitt|Wetteldorf Richtschnitt section]], [[Wetteldorf]], [[Eifel]], [[Germany]]
| upper_gssp_coords            = {{Coord|50.1496|N|6.4716|E|display=inline}}
| upper_gssp_accept_date       = 1985<ref>{{cite journal |last1=Ziegler |first1=W. |last2=Klapper |first2=G. |title=Stages of the Devonian System |journal=Episodes |date=June 1985 |volume=8 |issue=2 |pages=104–109 |doi=10.18814/epiiugs/1985/v8i2/006 |url=https://stratigraphy.org/gssps/files/eifelian.pdf |access-date=18 December 2020|doi-access=free }}</ref>
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}}

The '''Early Devonian''' is the first of three [[Epoch (geology)|epochs]] comprising the [[Devonian]] period, corresponding to the '''Lower Devonian''' [[Series (stratigraphy)|series]]. It lasted from {{period span|Early devonian}} and began with the [[Lochkovian]] Stage {{period span|Lochkovian}}, which was followed by the [[Pragian]] from {{period span|Pragian}} and then by the [[Emsian]], which lasted until the [[Middle Devonian]] began, {{ma|middle devonian|error=show}}.<ref name=ICSC>{{cite journal |last1=Cohen| first1= K.M.| last2= Finney|first2 = S.C.|last3 = Gibbard| first3 = P.L.| last4 =Fan|first4 = J.-X. |year=2013 |title=The ICS International Chronostratigraphic Chart| journal = Episodes|volume = 36| issue =3| pages= 199–204 | doi= 10.18814/epiiugs/2013/v36i3/002|url=https://stratigraphy.org/ICSchart/Cohen2013_Episodes.pdf |access-date=7 January 2021|doi-access= free}}</ref>
During this time, the first [[Ammonoidea|ammonoids]] appeared, descending from [[Bactritida|bactritoid]] [[Nautiloidea|nautiloids]]. Ammonoids during this time period were simple and differed little from their nautiloid counterparts. These ammonoids belong to the order [[Agoniatitida]], which in later epochs evolved to new ammonoid orders, for example [[Goniatite|Goniatitida]] and [[Clymeniida]]. This class of [[cephalopod]] molluscs would dominate the marine fauna until the beginning of the [[Mesozoic]] Era.

== References ==

{{Reflist}}

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[[Category:Early Devonian| ]]
[[Category:Geological epochs]]
[[Category:Devonian geochronology|*01]]


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