Givetian

The Givetian is one of two faunal stages in the Middle Devonian Period. It lasted from 387.7 million years ago to 382.7 million years ago. It was preceded by the Eifelian Stage and followed by the Frasnian Stage. It is named after the town of Givet in France. The oldest forests occurred during the late Givetian.^[7] The lower GSSP is located at Jebel Mech Irdane, Tafilalt, Morocco.

Givetian
387.7 ± 0.8 – 382.7 ± 1.6 Ma PreꞒ Ꞓ O S D C P T J K Pg N ↓
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
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 hemiansatus
Lower boundary GSSP	Jebel Mech Irdane, Tafilalt, Morocco 31°14′15″N 4°21′15″W / 31.2374°N 4.3541°W / 31.2374; -4.3541
Lower GSSP ratified	1994^[5]
Upper boundary definition	FAD of the conodont Ancyrodella rotundiloba
Upper boundary GSSP	Col du Puech de la Suque, Montagne Noire, France 43°30′12″N 3°05′12″E / 43.5032°N 3.0868°E / 43.5032; 3.0868
Upper GSSP ratified	1986^[6]

Name and definition

The Givetian Stage was proposed in 1879 by French geologist Jules Gosselet and was accepted for the higher stage of the Middle Devonian by the Subcommission on Devonian Stratigraphy in 1981.^[8]

References

1. Parry, S. F.; Noble, S. R.; Crowley, Q. G.; Wellman, C. H. (2011). "A high-precision U–Pb age constraint on the Rhynie Chert Konservat-Lagerstätte: time scale and other implications". Journal of the Geological Society. London: Geological Society. 168 (4): 863–872. doi:10.1144/0016-76492010-043.
2. Kaufmann, B.; Trapp, E.; Mezger, K. (2004). "The numerical age of the Upper Frasnian (Upper Devonian) Kellwasser horizons: A new U-Pb zircon date from Steinbruch Schmidt(Kellerwald, Germany)". The Journal of Geology. 112 (4): 495–501. Bibcode:2004JG....112..495K. doi:10.1086/421077.
3. Algeo, T. J. (1998). "Terrestrial-marine teleconnections in the Devonian: links between the evolution of land plants, weathering processes, and marine anoxic events". Philosophical Transactions of the Royal Society B: Biological Sciences. 353 (1365): 113–130. doi:10.1098/rstb.1998.0195.
4. "Chart/Time Scale". www.stratigraphy.org. International Commission on Stratigraphy.
5. Walliser, O.; Bultynck, P.; Weddige, K.; Becker, R.; House, M. (September 1995). "Definition of the Eifelian-Givetian Stage boundary". Episodes. 18 (3): 107–115. doi:10.18814/epiiugs/1995/v18i3/002. Retrieved 19 December 2020.
6. Klapper, Gilbert; Feist, Raimund; House, Michael (June 1987). "Decision on the Boundary Stratotype for the Middle/Upper Devonian Series Boundary". Episodes. 10 (2): 97–101. doi:10.18814/epiiugs/1987/v10i2/004. Retrieved 19 December 2020.
7. Becker, R.T.; Gradstein, F.M.; Hammer, O. (2012). "Chapter 22 - The Devonian Period". In Gradstein, F.M.; Ogg, J.G.; Schmitz, M.D.; Ogg, G.M. (eds.). The Geologic Timescale 2012. Elsevier. p. 578. doi:10.1016/b978-0-444-59425-9.00022-6. ISBN 978-0-444-59425-9.
8. Préat, Alain; Bultynck, Pierre (2006). "Givetian" (PDF). Geologica Belgica. 9 (1–2): 9–18. Retrieved 12 March 2013.

31°14′15″N 4°21′15″W / 31.2375°N 4.3542°W / 31.2375; -4.3542

Further reading

• Klug, C (2002). "Quantitative stratigraphy and taxonomy of late Emsian and Eifelian ammonoids of the eastern Anti-Atlas (Morocco)". Courier Forschungsinstitut Senckenberg. 238: 1–109.