World Library  
Flag as Inappropriate
Email this Article


Article Id: WHEBN0003026433
Reproduction Date:

Title: Roadian  
Author: World Heritage Encyclopedia
Language: English
Subject: Wordian, Permian, Kungurian, Changhsingian, Wuchiapingian
Collection: Geochronology, Geologic Time Scale, Geological Ages, Permian, Permian Geochronology
Publisher: World Heritage Encyclopedia


Age (Ma)
Triassic Lower/
Induan younger
Permian Lopingian Changhsingian 252.2–254.1
Wuchiapingian 254.1–259.8
Guadalupian Capitanian 259.8–265.1
Wordian 265.1–268.8
Roadian 268.8–272.3
Cisuralian Kungurian 272.3–283.5
Artinskian 283.5–290.1
Sakmarian 290.1–295.0
Asselian 295.0–298.9
Carboniferous Pennsylvanian Gzhelian older
Subdivision of the Permian system
according to the ICS (Geologic Time Scale 2013).[1]
Hercosestria cribrosa, A reef-forming Roadian brachiopod from the Glass Mountains of Texas.

In the geologic timescale, the Roadian is an age or stage of the Permian. It is the earliest or lower of three subdivisions of the Guadalupian epoch or series. The Roadian lasted between 272.3 ± 0.5 and 268.8 ± 0.5 million years ago (Ma). It was preceded by the Kungurian and followed by the Wordian.[2]


  • Stratigraphy 1
  • Biodiversity 2
  • References 3
    • Notes 3.1
    • Literature 3.2
  • External links 4


The Wordian stage was introduced into scientific literature in 1916 and was named after the Word Formation of the North American Permian Basin. In 1961, the regional timescale used for the southeastern US had the Wordian and Capitanian as subdivisions of the Guadalupian.[3] Efforts to correlate the Permian stratigraphy of the southeastern US with that of Russia led to the conclusion that between the Wordian stage and the Russian Artinskian stage, another stage needed to be introduced.[4] This stage, the Roadian stage, was established in 1968 and took its name from the Road Canyon Member, the lower (oldest) part of the Word Formation.[5] The stage was added to the internationally used IUGS timescale in 2001.[6]

The base of the Roadian is defined as the place in the stratigraphic record where fossils of conodont species Jinogondolella nankingensis first appears. The global reference profile for the base (the GSSP) is located in Stratotype Canyon in the Guadalupe Mountains, Texas (). The top of the Roadian (the base of the Wordian stage) is at the first appearance of fossils of conodont species Jinogondolella aserrata.


Olson’s Extinction, a worldwide loss of terrestrial vertebrate life occurred during the Early Guadalupian (Roadian, Wordian).[7]



  1. ^
  2. ^ See Gradstein et al. (2004) for a detailed geologic timescale
  3. ^ Glenister & Furnish (1961)
  4. ^ Nassichuk (1964)
  5. ^ Furnish & Glenister (1968)
  6. ^ The current ICS' subdivision of the Guadalupian epoch/series was officially proposed by Glenister et al. (1999)
  7. ^


  • Glenister, B.F. & Furnish, W.M.; 1961: The Permian ammonoids of Australia, Journal of Paleontology 35(4), pp 673–736.
  • Glenister, B.F.; Wardlaw, B.R.; Lambert, L.L.; Spinosa, C.; Bowring, S.A.; Erwin, D.H.; Menning, M. & Wilde, G.L.; 1999: Proposal of Guadalupian and Component Roadian, Wordian and Capitanian Stages as International Standards for the Middle Permian Series, Permophiles 34: pp 3–11.
  • Gradstein, F.M.; Ogg, J.G. & Smith, A.G.; 2004: A Geologic Time Scale 2004, Cambridge University Press
  • Nassichuk, W.W.; 1964: Pennsylvanian and Permian rocks in the Parry Islands Group, Canadian Arctic Archipelago, Report of activities, field

External links

  • GeoWhen Database - Roadian
  • Upper Paleozoic stratigraphic chart at the website of the subcommission for stratigraphic information of the ICS
This article was sourced from Creative Commons Attribution-ShareAlike License; additional terms may apply. World Heritage Encyclopedia content is assembled from numerous content providers, Open Access Publishing, and in compliance with The Fair Access to Science and Technology Research Act (FASTR), Wikimedia Foundation, Inc., Public Library of Science, The Encyclopedia of Life, Open Book Publishers (OBP), PubMed, U.S. National Library of Medicine, National Center for Biotechnology Information, U.S. National Library of Medicine, National Institutes of Health (NIH), U.S. Department of Health & Human Services, and, which sources content from all federal, state, local, tribal, and territorial government publication portals (.gov, .mil, .edu). Funding for and content contributors is made possible from the U.S. Congress, E-Government Act of 2002.
Crowd sourced content that is contributed to World Heritage Encyclopedia is peer reviewed and edited by our editorial staff to ensure quality scholarly research articles.
By using this site, you agree to the Terms of Use and Privacy Policy. World Heritage Encyclopedia™ is a registered trademark of the World Public Library Association, a non-profit organization.

Copyright © World Library Foundation. All rights reserved. eBooks from World eBook Library are sponsored by the World Library Foundation,
a 501c(4) Member's Support Non-Profit Organization, and is NOT affiliated with any governmental agency or department.