Olenekian

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System/
Period
Series/
Epoch
Stage/
Age
Age (Ma)
Jurassic Lower/
Early
Hettangian younger
Triassic Upper/
Late
Rhaetian 201.3–208.5
Norian 208.5–~228
Carnian ~228–~235
Mid/
Middle
Ladinian ~235–~242
Anisian ~242–247.2
Lower/
Early
Olenekian 247.2–251.2
Induan 251.2–252.2
Permian Lopingian Changhsingian older
Subdivision of the Triassic system
according to the IUGS, as of July 2012.

In the geologic timescale, the Olenekian is an age in the Early Triassic epoch or a stage in the Lower Triassic series. It spans the time between 251.2 Ma and 247.2 Ma (million years ago).[1] The Olenekian follows the Induan and is followed by the Anisian.[2]

The Olenekian saw the deposition of a large part of the Buntsandstein in Europe. Archosaurs - a group encompassing crocodiles, pterosaurs, dinosaurs, and ultimately birds - are diapsid reptiles that first evolved from Archosauriform ancestors during the Olenekian.

The Olenekian is roughly coeval with the regional Yongningzhenian stage used in China.

Stratigraphic definitions[edit]

The Olenekian stage was introduced into scientific literature by Russian stratigraphers in 1956.[3] The stage is named after Olenëk in Siberia. Before the subdivision in Olenekian and Induan became established, both stages formed the Scythian stage, which has since disappeared from the official timescale.

The base of the Olenekian is at the lowest occurrence of the ammonites Hedenstroemi or Meekoceras gracilitatis, and of the conodont Neospathodus waageni. It is defined as ending near the lowest occurrences of genera Japonites, Paradanubites, and Paracrochordiceras; and of the conodont Chiosella timorensis. A GSSP (global reference profile for the base) has in 2009 not yet been established.

The Olenekian is sometimes divided into the Smithian and the Spathian subages or substages.

Palaeontology[edit]

Archosauromorphs[edit]

Archosauromorphs of the Olenekian
Taxa Presence Location Description Images
Madygen, Kyrgyzstan

†Ichthyosaurs[edit]

Ichthyosauria of the Olenekian
Taxa Presence Location Description Images
Japan, Canada

Therapsids[edit]

Therapsids of the Olenekian
Taxa Presence Location Description Images

See also[edit]

References[edit]

Notes[edit]

  1. ^ According to Gradstein (2004). Brack et al. (2005) give 251 to 248 Ma
  2. ^ See for a detailed geologic timescale Gradstein et al. (2004)
  3. ^ Kiparisova & Popov (1956)

Literature[edit]

  • 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.
  • Gradstein, F.M.; Ogg, J.G. & Smith, A.G.; 2004: A Geologic Time Scale 2004, Cambridge University Press.
  • Kiparisova, L.D. & Popov, J.N.; 1956: Расчленение нижнего отдела триасовой системы на ярусы (Subdivision of the lower series of the Triassic System into stages), Doklady Akademii Nauk SSSR 109(4), pp 842–845 (Russian).

External links[edit]

Triassic Period
Lower/Early Triassic Middle Triassic Upper/Late Triassic
Induan |Olenekian Anisian | Ladinian Carnian | Norian
Rhaetian