Lochkovian
The Lochkovian Age/Stage within the Early Devonian (ICS 2026/06); about 419.62–413.02 Ma.
Language and route: Czech place-name → international English. Czech place-name → international English. Name-source: Lochkov, now a Prague district, Czech Republic.
Literal gloss: named after Lochkov, now a Prague district, Czech Republic
The name and its history
Regional Lochkov terminology precedes international 1985 agreement; precise first stage coinage not assigned without original citation · Regional Lochkov terminology precedes international 1985 agreement; precise first stage coinage not assigned without original citation
- What does the word literally mean?
- Named from Lochkov, now a Prague district, Czech Republic.
- What did the original author mean?
- A Bohemian regional unit based on Lochkov-area strata; later selected as the first internationally agreed Devonian age.
- Why was the name needed?
- Lower Devonian Gedinnian/Siegenian faunal and rock boundaries in the Ardenne–Rhenish region were unsuitable as universal subdivisions, while defining the Silurian–Devonian transition had long been contentious.
- What evidence supported the original concept?
- At Klonk, Czech Republic, an international boundary is close to the first appearance of graptolite Uncinatograptus uniformis, supported by other fossils.
- How has geology changed the concept?
- A Czech local label took over as the basal Devonian stage, superseding internationally used regional names. Its GSSP does not lie in Lochkov itself.
Further historical context
*Original use.* A Bohemian regional unit based on Lochkov-area strata; later selected as the first internationally agreed Devonian age.
*Historical problem.* Lower Devonian Gedinnian/Siegenian faunal and rock boundaries in the Ardenne–Rhenish region were unsuitable as universal subdivisions, while defining the Silurian–Devonian transition had long been contentious.
*Evolution.* A Czech local label took over as the basal Devonian stage, superseding internationally used regional names. Its GSSP does not lie in Lochkov itself.
Editorial qualification
The first historical use of the exact name at stage rank is not established here; international 1985 agreement does not prove first coinage.
Related names
Devonian · Early Devonian · Pragian · Emsian
Sources
- ICS International Chronostratigraphic Chart, 2026/06 — Current nomenclature, rank and numerical age
- ICS official Lochkovian GSSP — International boundary stratotype and correlation evidence
- Ziegler & Klapper (1985), international revision of Devonian stages — Historical naming, original claim or scholarly review; see confidence note
- 2024 scholarly review of rejected Belgian lower Devonian stages — Historical naming, original claim or scholarly review; see confidence note
- ICS Devonian Subcommission, full sequence — Cross-check order and stage nomenclature