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Emsian

Third stage of the Devonian

Emsian
407.6 ± 2.6 – 393.3 ± 1.2 Ma PreꞒ Ꞓ O S D C P T J K Pg N
Paleogeography of the Emsian, 400 Ma
Chronology
−420 — – −415 — – −410 — – −405 — – −400 — – −395 — – −390 — – −385 — – −380 — – −375 — – −370 — – −365 — – −360 — – Paleozoic S Devonian C M Přídolí Early Mid Late EM Lochkovian Pragian Emsian Eifelian Givetian Frasnian Famennian Tournai.           ← Rhynie chert[1] ← Hangenberg event, Famennian glaciation ← Kellwasser event (Late Devonian extinction)[2] ← Widespread[3] shrubs & trees ← Hunsrück fauna Subdivision of the Devonian according to the ICS, as of 2021.[4] Vertical axis scale: millions of years ago.
Etymology
Name formality	Formal
Name ratified	1985
Usage information
Celestial body	Earth
Regional usage	Global (ICS)
Time scale(s) used	ICS Time Scale
Definition
Chronological unit	Age
Stratigraphic unit	Stage
Time span formality	Formal
Lower boundary definition	FAD of the conodont Polygnathus kitabicus
Lower boundary GSSP	Zinzil'ban Gorge, Uzbekistan 39°12′00″N 67°18′20″E / 39.2000°N 67.3056°E / 39.2000; 67.3056
Lower GSSP ratified	1995[5]
Upper boundary definition	FAD of the conodont Polygnathus costatus partitus
Upper boundary GSSP	Wetteldorf Richtschnitt section, Wetteldorf, Eifel, Germany 50°08′59″N 6°28′18″E / 50.1496°N 6.4716°E / 50.1496; 6.4716
Upper GSSP ratified	1985[6]

The Emsian is one of three faunal stages in the Early Devonian Epoch. It lasted from 407.6 ± 2.6 million years ago to 393.3 ± 1.2 million years ago. It was preceded by the Pragian Stage and followed by the Eifelian Stage. It is named after the Ems river in Germany.^[7] The GSSP is located in the Zinzil'ban Gorge in the Kitab State Geological ReserveofUzbekistan, 35 centimetres (14 in) above the contact with the Madmon Formation.

In North America the Emsian Stage is represented by SawkillorSawkillian time.

Biological events[edit]

During this period, earliest known agoniatitid ammonoid fossils began appearing within this stage after first appearing in previous stage and began to evolutionarily radiate within this stage, in which a new ammonoid order Goniatitida rises in the end of Zlichovian stage (Siberian representation; corresponds to early Eifelian and after the end of Early Devonian, before 391.9 mya).^[8][9] Later agoniatitid ammonoids would die out in the Taghanic event in the upper middle Givetian. Goniatite ammonoids would give rise to further ammonoid orders, thus starting ammonoid dominance of marine fossils in further periods until their end at the Cretaceous-Paleogene mass extinction event.

References[edit]

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