In the geologic timescale, the Anisian is the lower stage or earliest age of the Middle Triassic series or epoch and lasted from 247.2 million years ago until 242 million years ago.[7] The Anisian Age succeeds the Olenekian Age (part of the Lower Triassic Epoch) and precedes the Ladinian Age.

Anisian
247.2 – ~242 Ma
Untere Sulfatschichten Mittlerer Muschelkalk 030509.jpg
The Muschelkalk in Europe is mainly Anisian aged
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
Lower boundary definition candidates
Lower boundary GSSP candidate section(s)
Upper boundary definitionFAD of the Ammonite Eoprotrachyceras curionii
Upper boundary GSSPBagolino, Lombardian pre-Alps, Italy
45°49′09″N 10°28′16″E / 45.8193°N 10.4710°E / 45.8193; 10.4710
GSSP ratified2005[6]

Stratigraphic definitionsEdit

The stage and its name were established by Austrian geologists Wilhelm Heinrich Waagen and Carl Diener in 1895. The name comes from Anisus, the Latin name of the river Enns. The original type locality is at Großreifling in the Austrian state of Styria.

The base of the Anisian Stage (also the base of the Middle Triassic series) is sometimes laid at the first appearance of conodont species Chiosella timorensis in the stratigraphic record. Other stratigraphers prefer to use the base of magnetic chronozone MT1n. There is no accepted global reference profile for the base, but one (GSSP or golden spike) was proposed at a flank of the mountain Deşli Caira in the Romanian Dobruja.[8]

The top of the Anisian (the base of the Ladinian) is at the first appearance of ammonite species Eoprotrachyceras curionii and the ammonite family Trachyceratidae. The conodont species Neogondolella praehungarica appears at the same level.

Especially in Central Europe the Anisian Stage is sometimes subdivided into four substages: Aegean, Bythinian, Pelsonian and Illyrian.

The Anisian contains six ammonite biozones:

ReferencesEdit

NotesEdit

  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. ^ Brack, Peter; Rieber, Hans; Nicora, Alda; Mundil, Roland (December 2005). "The Global boundary Stratotype Section and Point (GSSP) of the Ladinian Stage (Middle Triassic) at Bagolino (Southern Alps, Northern Italy) and its implications for the Triassic time scale". Episodes. 28 (4). doi:10.18814/epiiugs/2005/v28i4/001. Retrieved 23 December 2020.
  7. ^ According to Gradstein et al. (2004); Brack et al. (2005) give 248 to 241 Ma
  8. ^ The GSSP was proposed by Grǎdinaru et al. (2007)

LiteratureEdit

  • Brack, P.; Rieber, H.; Nicora, A. & Mundil, R.; 2005: The Global boundary Stratotype Section and Point (GSSP) of the Ladinian Stage (Middle Triassic) at Bagolino (Southern Alps, Northern Italy) and its implications for the Triassic time scale, Episodes 28(4), pp. 233–244.
  • Grǎdinaru, E.; Orchard, M.J.; Nicora, A.; Gallet, Y.; Besse, J.; Krystyn, L.; Sobolev, E.S.; Atudorei, N.-V. & Ivanova, D.; 2007: The Global Boundary Stratotype Section and Point (GSSP) for the base of the Anisian Stage: Deşli Caira Hill, North Dobrogea, Romania, Albertiana 36, pp. 54–71.
  • Gradstein, F.M.; Ogg, J.G. & Smith, A.G.; 2004: A Geologic Time Scale 2004, Cambridge University Press.

External linksEdit

Coordinates: 45°04′27″N 28°48′08″E / 45.0742°N 28.8022°E / 45.0742; 28.8022