Gzhelian

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Gzhelian
303.7 ± 0.1 – 298.9 ± 0.15 Ma
↓
Romer's Gap
Subdivision of the Carboniferous according to the ICS, as of 2021.[1]

Vertical axis scale: millions of years ago
EtymologyName formalityFormalUsage informationCelestial body
AgeStratigraphic unitStageTime span formalityFormalType sectionGzhel horizon, Ghzel, Moscow Oblast, RussiaLower boundary definitionNot formally definedLower boundary definition candidatesFAD of the Conodont Idiognathodus simulator[2]
Lower boundary GSSP candidate section(s) Upper boundary definitionFAD of the Conodont
morphotype Streptognathodus wabaunsensis chronoclineUpper boundary GSSPAidaralash, Ural Mountains, Kazakhstan
50°14′45″N 57°53′29″E / 50.2458°N 57.8914°E / 50.2458; 57.8914Upper GSSP ratified1996[3]

The Gzhelian (

Ma.[4] It follows the Kasimovian age/stage and is followed by the Asselian age/stage, the oldest subdivision of the Permian
system.

The Gzhelian is more or less coeval with the Stephanian Stage of the regional stratigraphy of Europe.

Name and definition

The Gzhelian is named after the Russian village of Gzhel (Russian: Гжель), nearby Ramenskoye, not far from Moscow. The name and type locality were defined by Sergei Nikitin (1851–1909) in 1890.

3D model icon Photogrammetry model of geology outcrop in Gzhel (2022)

The base of the Gzhelian is at the first appearance of the Fusulinida genera Daixina, Jigulites and Rugosofusulina, or at the first appearance of the conodont Streptognathodus zethus. The top of the stage (the base of the Permian system) is at the first appearance of the conodont Streptognathodus isolatus within the Streptognathus "wabaunsensis" chronocline.[5] Six metres (20 ft) higher in the reference profile, the Fusulinida species Sphaeroschwagerina vulgaris aktjubensis appears.

Currently, a

Belaya river) at the edge of the hamlet of Krasnoussolsky, about 120 kilometres (75 mi) southeast of Ufa and 60 kilometres (37 mi) northeast of Sterlitamak (in Bashkortostan).[6]

Biozones

The Gzhelian Stage is subdivided into five biozones, based on the conodont genus Streptognathodus:

  • Streptognathodus wabaunsensis and Streptognathodus bellus Zone
  • Streptognathodus simplex Zone
  • Streptognathodus virgilicus Zone
  • Streptognathodus vitali Zone
  • Streptognathodus simulator Zone

References

  1. ^ "Chart/Time Scale". www.stratigraphy.org. International Commission on Stratigraphy.
  2. ^ a b "Global Boundary Stratotype Section and Point". International Commission of Stratigraphy. Retrieved 23 December 2020.
  3. ^ Davydov et al. 1998.
  4. Cambridge University
    Press
  5. doi:10.18814/epiiugs/1998/v21i1/003. Archived from the original
    (PDF) on 2007-09-28. Retrieved 2007-09-28.
  6. ^ Chernykh, V.V.; Chuvashov, B.I.; Davydov, V.I.; Schmitz, M. & Snyder, W.S.; 2006: Usolka section (southern Urals, Russia): a potential candidate for GSSP to define the base of the Gzhelian Stage in the global chronostratigraphic scale Geologija 49(2): pp 205–217, "Usolka section (southern Urals, Russia): a potential candidate for GSSP to define the base of the Gzhelian Stage in the global chronostratigraphic scale" (PDF). Archived from the original (PDF) on 2007-12-14. Retrieved 2007-12-14.

External links

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