Wordian
The age of the Guadalupian interval (Permian), approximately 266.9–264.28 Ma according to the ICS June 2026 chart.
Language and route: English surname-derived locality/formation name. English surname-derived locality/formation name → stratigraphic English. Named after Word Formation, Glass Mountains, Texas.
Literal gloss: from the Word Formation
The name and its history
Udden et al. (1916 formation); Glenister & Furnish (1961 at chronostratigraphic rank) · See attributed dates and cited original / standardisation works; first-use priority qualified where noted
- What does the word literally mean?
- From the word formation. Immediate scientific language-route: English surname-derived locality/formation name → stratigraphic English. This is a locality-based or geographical term, not a description of a universal geological event.
- What did the original author mean?
- Originally the lithostratigraphic Word Formation, then a chronostratigraphic interval distinguished by marine fossil assemblages.
- Why was the name needed?
- The Word Formation supplied a named middle Permian fossil-bearing succession; ammonoid/faunal comparisons led to reuse of the older lithostratigraphic label as a stage.
- What evidence supported the original concept?
- Distinct ammonoid and fusulinid faunas and the stratigraphic relationship of Word, Road Canyon and Capitan rock units supported American regional subdivision.
- How has geology changed the concept?
- Adopted as the middle of three globally standard Guadalupian stages; formation first-use is not stage first-use.
Further historical context
*Naming and context.* The Word Formation supplied a named middle Permian fossil-bearing succession; ammonoid/faunal comparisons led to reuse of the older lithostratigraphic label as a stage.
*Evidence and later scope.* Distinct ammonoid and fusulinid faunas and the stratigraphic relationship of Word, Road Canyon and Capitan rock units supported American regional subdivision. Adopted as the middle of three globally standard Guadalupian stages; formation first-use is not stage first-use.
Editorial qualification
Do not infer that the word derives from English word, ‘speech’; it is a proper name.
Related names
Permian · Guadalupian · Roadian · Capitanian · Fossil · Ammonoid · Stratigraphy · Lithostratigraphy
Sources
- ICS International Chronostratigraphic Chart (June 2026) — Current formal unit, order, rank and numerical age
- Glenister et al. (1999), Proposal for Roadian–Capitanian standards — Near-contemporaneous evidence for priority, naming routes and correlation
- Jin et al. (1997), Permian chronostratigraphic subdivisions, Episodes — International decision to adopt Urals, Texas and South China tripartition