Rhaetian

For the Alpine people of antiquity, see Rhaetians. For their language, see Rhaetian language.
Rhaetian
~208.5 – 201.4 ± 0.2 Ma
Chronology
Etymology
Name formalityFormal
Usage information
Celestial bodyEarth
Regional usageGlobal (ICS)
Time scale(s) usedICS Time Scale
Definition
Chronological unitAge
Stratigraphic unitStage
Time span formalityFormal
Lower boundary definitionNot formally defined[6]
Lower boundary definition candidates
Lower boundary GSSP candidate section(s)
Upper boundary definitionFAD of the Ammonite Psiloceras spelae tirolicum
Upper boundary GSSPKuhjoch section, Karwendel mountains, Northern Calcareous Alps, Austria
47°29′02″N 11°31′50″E / 47.4839°N 11.5306°E / 47.4839; 11.5306
Upper GSSP ratified2010[8]

The Rhaetian is the latest age of the Triassic Period (in geochronology) or the uppermost stage of the Triassic System (in chronostratigraphy). It was preceded by the Norian and succeeded by the Hettangian (the lowermost stage or earliest age of the Jurassic).[9] The base of the Rhaetian lacks a formal GSSP, though candidate sections include Steinbergkogel in Austria (since 2007) and Pignola-Abriola in Italy (since 2016). The end of the Rhaetian (and the base of the overlying Hettangian Stage) is more well-defined. According to the current ICS (International Commission on Stratigraphy) system, the Rhaetian ended 201.4 ± 0.2 Ma (million years ago).[10]

In 2010, the base of the Rhaetian (i.e. the Norian-Rhaetian boundary) was voted to be defined based on the first appearance of Misikella posthernsteini, a marine conodont.[11] However, there is still much debate over the age of this boundary,[12] as well as the evolution of M. posthernsteini.[13] The most comprehensive source of precise age data for the Late Triassic comes from astrochronologically-constrained terrestrial strata of the Newark basin in the eastern United States.[14] Correlating the Newark basin to marine sections encompassing the Norian-Rhaetian boundary is mainly achieved via magnetostratigraphy, though such correlations are subject to debate and revision. Some authors have suggested that the Rhaetian lasted less than 5 million years using magnetostratigraphy from Turkish strata and a presumed gap or unconformity in Newark strata.[15][16] However, both of these lines of evidence have been met with skepticism.[17][18][19]

A commonly cited approximation of 208.5 Ma (used by the ICS since 2012) is based on a "long-Rhaetian" hypothesis reconstructed from the Steinbergkogel GSSP candidate.[19][20][21][22] Most recently, aspects of the "short-Rhaetian" hypothesis have been revived by radiometric dating of Peruvian bivalve extinctions and magnetostratigraphy at the Pignola-Abriola GSSP candidate. These studies suggest that the base of the Rhaetian was close to 205.5 Ma.[23][24]

During the Rhaetian, Pangaea began to break up, though the Atlantic Ocean was not yet formed.

  1. ^ Widmann, Philipp; Bucher, Hugo; Leu, Marc; et al. (2020). "Dynamics of the Largest Carbon Isotope Excursion During the Early Triassic Biotic Recovery". Frontiers in Earth Science. 8 (196): 196. Bibcode:2020FrEaS...8..196W. doi:10.3389/feart.2020.00196.
  2. ^ McElwain, J. C.; Punyasena, S. W. (2007). "Mass extinction events and the plant fossil record". Trends in Ecology & Evolution. 22 (10): 548–557. doi:10.1016/j.tree.2007.09.003. PMID 17919771.
  3. ^ Retallack, G. J.; Veevers, J.; Morante, R. (1996). "Global coal gap between Permian–Triassic extinctions and middle Triassic recovery of peat forming plants". GSA Bulletin. 108 (2): 195–207. Bibcode:1996GSAB..108..195R. doi:10.1130/0016-7606(1996)108<0195:GCGBPT>2.3.CO;2. Retrieved 2007-09-29.
  4. ^ Payne, J. L.; Lehrmann, D. J.; Wei, J.; Orchard, M. J.; Schrag, D. P.; Knoll, A. H. (2004). "Large Perturbations of the Carbon Cycle During Recovery from the End-Permian Extinction". Science. 305 (5683): 506–9. Bibcode:2004Sci...305..506P. doi:10.1126/science.1097023. PMID 15273391. S2CID 35498132.
  5. ^ Ogg, James G.; Ogg, Gabi M.; Gradstein, Felix M. (2016). "Triassic". A Concise Geologic Time Scale: 2016. Elsevier. pp. 133–149. ISBN 978-0-444-63771-0.
  6. ^ a b c d e f g "Global Boundary Stratotype Section and Point". International Commission of Stratigraphy. Retrieved 23 December 2020.
  7. ^ Rigo, Manuel; Bertinelli, Angela; Concheri, Giuseppe; Gattolin, Giovanni; Godfrey, Linda; Katz, Miriam E.; Maron, Matteo; Mietto, Paolo; Muttoni, Giovanni; Sprovieri, Mario; Stellin, Fabio; Mariachiara, Zaffani (2016). "The Pignola-Abriola section (southern Apennines, Italy): a new GSSP candidate for the base of the Rhaetian Stage". Lethaia. 49 (3): 287–306. Bibcode:2016Letha..49..287R. doi:10.1111/let.12145. ISSN 1502-3931.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  8. ^ Hillebrandt, A.v.; Krystyn, L.; Kürschner, W.M.; Bonis, N.R.; Ruhl, M.; Richoz, S.; Schobben, M. A. N.; Urlichs, M.; Bown, P.R.; Kment, K.; McRoberts, C.A.; Simms, M.; Tomãsových, A (September 2013). "The Global Stratotype Sections and Point (GSSP) for the base of the Jurassic System at Kuhjoch (Karwendel Mountains, Northern Calcareous Alps, Tyrol, Austria)". Episodes. 36 (3): 162–198. CiteSeerX 10.1.1.736.9905. doi:10.18814/epiiugs/2013/v36i3/001. S2CID 128552062.
  9. ^ See Gradstein et al. (2004)
  10. ^ Schoene, Blair; Guex, Jean; Bartolini, Annachiara; Schaltegger, Urs; Blackburn, Terrence J. (2010-05-01). "Correlating the end-Triassic mass extinction and flood basalt volcanism at the 100 ka level". Geology. 38 (5): 387–390. Bibcode:2010Geo....38..387S. doi:10.1130/G30683.1. ISSN 0091-7613.
  11. ^ Cite error: The named reference :6 was invoked but never defined (see the help page).
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  17. ^ Muttoni, Giovanni; Kent, Dennis V.; Jadoul, Flavio; Olsen, Paul E.; Rigo, Manuel; Galli, Maria Teresa; Nicora, Alda (2010-01-01). "Rhaetian magneto-biostratigraphy from the Southern Alps (Italy): Constraints on Triassic chronology" (PDF). Palaeogeography, Palaeoclimatology, Palaeoecology. 285 (1): 1–16. Bibcode:2010PPP...285....1M. doi:10.1016/j.palaeo.2009.10.014. ISSN 0031-0182. S2CID 2559660.
  18. ^ Cite error: The named reference :11 was invoked but never defined (see the help page).
  19. ^ a b Cite error: The named reference :4 was invoked but never defined (see the help page).
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  22. ^ Brack et al. give 207 to 201 million years ago
  23. ^ Cite error: The named reference :12 was invoked but never defined (see the help page).
  24. ^ Cite error: The named reference :5 was invoked but never defined (see the help page).