Pragian
| Pragian | |||||||||||||||||
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| Chronology | |||||||||||||||||
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| Etymology | |||||||||||||||||
| Name formality | Formal | ||||||||||||||||
| Name ratified | 1985[5] | ||||||||||||||||
| 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 conodonts Eognathodus sulcatus and Latericriodus steinachensis Morph beta | ||||||||||||||||
| Lower boundary GSSP | Velká Chuchle quarry, Prague, Czech Republic 50°00′53″N 14°22′21″E / 50.0147°N 14.3726°E | ||||||||||||||||
| Lower GSSP ratified | 1989[5] | ||||||||||||||||
| Upper boundary definition | FAD of the conodont Polygnathus kitabicus | ||||||||||||||||
| Upper boundary GSSP | Zinzil'ban Gorge, Uzbekistan 39°12′00″N 67°18′20″E / 39.2000°N 67.3056°E | ||||||||||||||||
| Upper GSSP ratified | 1995[6] | ||||||||||||||||
The Pragian is one of three faunal stages in the Early Devonian Epoch. It lasted from 413.02 ± 1.91 million years ago to 410.62 ± 1.95 million years ago. It was preceded by the Lochkovian Stage and followed by the Emsian Stage. The most important Lagerstätte of the Pragian is Rhynie chert in Scotland. It is named after the city of Prague.[7] The GSSP is located within the Prague Formation at Velká Chuchle, Prague.
In North America the Pragian Stage is represented by Siegenian or Deerparkian time.
Pragian life
The first ammonoids (order Agoniatitida) appeared in later parts of this stage (at the lower boundary of the Zlichovian stage as it was known in Siberian representations). They were descended from bactritoid nautiloid ancestors, which also appeared in this stage before experiencing evolutionary radiations in the next stage.[8]
References
- ^ Kaufmann, Bernd; Trapp, Endres; Mezger, Klaus (July 2004). "The numerical age of the Upper Frasnian (Upper Devonian) Kellwasser horizons: A new U-Pb zircon date from Steinbruch Schmidt (Kellerwald, Germany)" (PDF). The Journal of Geology. 112 (4): 495–501. Bibcode:2004JG....112..495K. doi:10.1086/42107. eISSN 1537-5269. ISSN 0022-1376. JSTOR 421077. LCCN 25013118. OCLC 1608377. S2CID 129963970. Archived from the original (PDF) on February 10, 2024. Retrieved December 16, 2025.
- ^ Algeo, Thomas; Scheckler, Stephen E. (January 29, 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. eISSN 1471-2970. PMC 1692181. S2CID 84656565.
- ^ Parry, Stephen F.; Noble, Stephen R.; Crowley, Quentin C.; Wellman, Charles H. (June 15, 2011). "A high-precision U–Pb age constraint on the Rhynie Chert Konservat-Lagerstätte: time scale and other implications" (PDF). Journal of the Geological Society. 168 (4). Geological Society of London: 863–872. Bibcode:2011JGSoc.168..863P. doi:10.1144/0016-76492010-043. eISSN 2041-479X. ISSN 0016-7649. LCCN 79641612. OCLC 1934542. S2CID 128679831. Archived (PDF) from the original on July 11, 2025. Retrieved December 16, 2025.
- ^ "International Chronostratigraphic Chart" (PDF). International Commission on Stratigraphy. December 2024. Retrieved October 23, 2025.
- ^ a b Chlupac, Ivo; Oliver, William (June 1989). "Decision on the Lochkovian-Pragian Boundary Stratotype (Lower Devonian)" (PDF). Episodes. 12 (2): 109–114. doi:10.18814/epiiugs/1989/v12i2/014. Retrieved 18 December 2020.
- ^ Yolkin, E.; Kim, A.; Weddige, K.; Talent, J.; House, M. (December 1997). "Definition of the Pragian/Emsian Stage boundary". Episodes. 20 (4): 235–240. doi:10.18814/epiiugs/1997/v20i4/005. Retrieved 18 December 2020.
- ^ "Pragian stage". Encyclopedia Britannica. Retrieved 2 October 2019.
- ^ Kröger, Björn (2009). "Nautiloids before and during the origin of ammonoids in a Siluro-Devonian section in the Tafilalt, Anti-Atlas, Morocco". Special Papers in Palaeontology. 79. ISBN 978-1-405-18770-1.