Ludfordian
The age of the Ludlow interval (Silurian), approximately 425.0–422.7 Ma according to the ICS June 2026 chart.
Language and route: English locality. English locality → international English. Named after Ludford village adjacent to Ludlow, Shropshire.
Literal gloss: named for Ludford
The name and its history
International Ludlow stage scheme; GSSP ratified 1980 · See attributed dates and cited original / standardisation works; first-use priority qualified where noted
- What does the word literally mean?
- Named for ludford. Immediate scientific language-route: English locality → international English. This is a locality-based or geographical term, not a description of a universal geological event.
- What did the original author mean?
- The upper part of the Ludlow succession, originally linked to Shropshire reference strata around Ludford.
- Why was the name needed?
- The younger part of Ludlow rock successions was separated at stage rank to stabilise correlations close to the Silurian–Devonian transition.
- What evidence supported the original concept?
- At the type region the boundary is placed near the base of the Leintwardine Formation; biostratigraphic correlation remains imperfect.
- How has geology changed the concept?
- The town-derived name is retained globally, whereas the lithostratigraphic boundaries and fossil marker interpretations have been reassessed.
Further historical context
*Naming and context.* The younger part of Ludlow rock successions was separated at stage rank to stabilise correlations close to the Silurian–Devonian transition.
*Evidence and later scope.* At the type region the boundary is placed near the base of the Leintwardine Formation; biostratigraphic correlation remains imperfect. The town-derived name is retained globally, whereas the lithostratigraphic boundaries and fossil marker interpretations have been reassessed.
Editorial qualification
The current ICS listing signals imprecise primary correlation at this boundary.
Related names
Silurian · Ludlow · Gorstian · Fossil · Lithostratigraphy · Biostratigraphy
Sources
- ICS International Chronostratigraphic Chart (June 2026) — Current formal unit, order, rank and numerical age
- ICS international GSSPs: Silurian stages and boundary issues — Modern formal references, rank, locations and correlation
- British Silurian Stratigraphy, Ludlow Series chapter — Stratigraphic history and original Ludlow mapping