Gzhelian

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System Subsystem/
Series
Stage Age (Ma)
Permian Cisuralian Asselian younger
Carboniferous Pennsylvanian Gzhelian 298.9 303.7
Kasimovian 303.7 307.0
Moscovian 307.0 315.2
Bashkirian 315.2 323.2
Mississippian Serpukhovian 323.2 330.9
Visean 330.9 346.7
Tournaisian 346.7 358.9
Devonian Late Famennian older
Subdivision of the Carboniferous system
according to the ICS, as of 2017.[1]

The Gzhelian is an age in the ICS geologic timescale or a stage in the stratigraphic column. It is the youngest stage of the Pennsylvanian, the youngest subsystem of the Carboniferous. The Gzhelian lasted from 303.7 to 298.9 Ma.[2] 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[edit]

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 (1850–1909) in 1890.

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.[3] Six meters higher in the reference profile, the Fusulinida species Sphaeroschwagerina vulgaris aktjubensis appears.

At the moment (2008), a golden spike for the Gzhelian stage is yet lacking. A candidate is a section along the Ussolka river (a tributary of the Belaya river) at the edge of the hamlet of Krasnoussolsky, about 120 kilometres south-east of Ufa and 60 kilometres north-east of Sterlitamak (in Bashkortostan).[4]

Biozones[edit]

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

Palaeontology[edit]

Amphibians[edit]

Reptiliomorphs[edit]

Temnospondyls of the Gzhelian
Taxa Presence Location Description Images
New Mexico

Temnospondyls[edit]

Temnospondyls of the Gzhelian
Taxa Presence Location Description Images
Nova Scotia, Canada

Arthropods[edit]

Arthropods of the Gzhelian
Taxa Presence Location Description Images
Scotland and northeastern North America
Pallero member, Bajo de Véliz Formation, Argentina

Synapsids[edit]

Synapsids of the Gzhelian
Taxa Presence Location Description Images

Remigiusberg Formation, Saar-Nahe Basin, Germany

Kasimovian-Asselian Ludwikowice Formation, Nowa Ruda, Poland
Kasimovian-Kungurian

Ada Formation, Oklahoma

Gzhelian-Artinskian New Mexico; Utah-Arizona border region, both in USA; possibly England The English specimen known as S?. brittanicus is now generally classified as Sphenacodontidae incertae sedis separate from the other Sphenacodon species so may need reassigning.

References[edit]

  1. ^ http://www.stratigraphy.org/index.php/ics-chart-timescale
  2. ^ Gradstein, F.M.; Ogg, J.G. & Smith, A.G.; 2004: A Geologic Time Scale 2004, Cambridge University Press
  3. ^ Davydov, V.I.; Glenister, B.F.; Spinosa, C.; Ritter, S.M.; Chernykh, V.V.; Wardlaw, B.R. & Snyder, W.S.; 1998: Proposal of Aidaralash as Global Stratotype Section and Point (GSSP) for base of the Permian System, Episodes 21(1): pp 11-18, "Archived copy" (PDF). Archived from the original (PDF) on 2007-09-28. Retrieved 2007-09-28.
  4. ^ 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, "Archived copy" (PDF). Archived from the original (PDF) on 2007-12-14. Retrieved 2007-12-14.

External links[edit]