Keuper
Uppermost of the three traditional lithostratigraphic groups of the Germanic Triassic; varied mudstones, marls, evaporites and other sedimentary rocks.
Language and route: Franconian dialect → German geology. Borrowed into scientific German from a vernacular term for distinctive marls/claystones in the Coburg region. Deeper proposed connections differ.
Literal gloss: regional name for variegated clay-rich rock
The name and its history
Attribution unresolved · Original publication not verified
- What does the word literally mean?
- Keuper entered German geology from a regional word for variegated, friable marl or claystone around Coburg. Its precise deeper derivation is not settled by that observation.
- What did the original author mean?
- A pre-existing German regional rock word supplied the name rather than a transparent Greek compound.
- Why was the name needed?
- The heterogeneous upper Germanic succession needed a practical name in Alberti’s Trias.
- What evidence supported the original concept?
- Regional marl, clay, gypsum/evaporite and sandstone successions were traced above Muschelkalk.
- How has geology changed the concept?
- The historic local unit cannot be mapped wholesale onto the globally defined Late Triassic; dialectal word origin itself is disputed.
Further historical context
According to Nitsch’s historical study, Leopold von Buch used the word for rock in 1822; Friedrich Hoffmann extended it to a stratigraphic unit in 1823, with early published adoption following soon after. Alberti incorporated it in his 1834 Trias formulation.
The name belongs to German regional lithostratigraphy and should not be treated as globally interchangeable with ‘Late Triassic’. See Triassic, Muschelkalk and Buntsandstein.
Editorial qualification
The German dialect source is supported; a further etymological claim about older roots should be flagged as tentative.
Related names
Triassic · Buntsandstein · Muschelkalk · Stratigraphy · Lithostratigraphy · Sedimentary
Sources
- E. Nitsch (1996), “Keuper 1820–34: Geburt eines stratigraphischen Begriffes”, Annals of Science 53, 489–500 — Historical adoption and vernacular origin
- International Field Workshop on the Triassic of Germany, field guide — History and Franconian term
- Duden, “Keuper” — Regional usage and proposed deeper connection