Middle Triassic

In the geologic timescale, the Middle Triassic is the second of three epochs of the Triassic period or the middle of three series in which the Triassic system is divided in chronostratigraphy. The Middle Triassic spans the time between 247.2 Ma and 237 Ma (million years ago). It is preceded by the Early Triassic Epoch and followed by the Late Triassic Epoch. The Middle Triassic is divided into the Anisian and Ladinian ages or stages.

Middle Triassic
Middle Triassic aged Muschelkalk (Schaumkalk) in Baden-Württemberg, Germany
Chronology
Etymology
Name formalityFormal
Usage information
Celestial bodyEarth
Regional usageGlobal (ICS)
Time scale(s) usedICS Time Scale
Definition
Chronological unitEpoch
Stratigraphic unitSeries
Time span formalityFormal
Lower boundary definitionNot formally defined
Lower boundary definition candidates
Lower boundary GSSP candidate section(s)
Upper boundary definitionFAD of the Ammonite Daxatina canadensis
Upper boundary GSSPPrati di Stuores, Dolomites, Italy
46.5269°N 11.9303°E / 46.5269; 11.9303
Upper GSSP ratified2008[6]

Formerly the middle series in the Triassic was also known as Muschelkalk. This name is now only used for a specific unit of rock strata with approximately Middle Triassic age, found in western Europe.

Middle Triassic fauna

Following the Permian–Triassic extinction event, the most devastating of all mass-extinctions, life recovered slowly. In the Middle Triassic, many groups of organisms reached higher diversity again, such as the marine reptiles (e.g. ichthyosaurs, sauropterygians, thallatosaurs), ray-finned fish and many invertebrate groups like molluscs (ammonoids, bivalves, gastropods).

During the Middle Triassic, there were no flowering plants, but instead there were ferns and mosses. Small dinosauriforms began to appear, like Nyasasaurus and the ichnogenus Iranosauripus.

References
  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. Mietto, Paolo; Manfrin, Stefano; Preto, Nereo; Rigo, Manuel; Roghi, Guido; Furin, Stefano; Gianolla, Piero; Posenato, Renato; Muttoni, Giovanni; Nicora, Alda; Buratti, Nicoletta; Cirilli, Simonetta; Spötl, Christoph; Ramezani, Jahandar; Bowring, Samuel (September 2012). "The Global Boundary Stratotype Section and Point (GSSP) of the Carnian Stage (Late Triassic) at Prati Di Stuores/Stuores Wiesen Section (Southern Alps, NE Italy)" (PDF). Episodes. 35 (3): 414–430. doi:10.18814/epiiugs/2012/v35i3/003. Retrieved 13 December 2020.


This article is issued from Wikipedia. The text is licensed under Creative Commons - Attribution - Sharealike. Additional terms may apply for the media files.