Middle Ordovician
The Middle Ordovician Epoch / corresponding Middle Ordovician Series; about 471.3–458.2 Ma.
Language and route: English, transparent ordinal adjective (not a historical proper-name coinage). English, transparent ordinal adjective (not a historical proper-name coinage). Name-source: descriptive position within the Ordovician succession.
Literal gloss: descriptive position within the Ordovician succession
The name and its history
No individual proposer: ordinal rank labels standardised through international usage and formal boundary agreements · No individual proposer: ordinal rank labels standardised through international usage and formal boundary agreements
- What does the word literally mean?
- English ordinal label for the descriptive position within the Ordovician succession. Not a separate Greek, Latin or regional etymological coinage.
- What did the original author mean?
- The middle part of Ordovician time as part of the threefold period subdivision, with the named stages Dapingian, Darriwilian.
- Why was the name needed?
- Geologists needed consistent time-series divisions rather than conflicting provincial rock-based subdivisions of the Ordovician.
- What evidence supported the original concept?
- Global stages (Dapingian, Darriwilian) and their boundary stratotypes, correlated primarily by fossils, define the modern limits.
- How has geology changed the concept?
- Early/Middle/Late label epochs in time; equivalent Lower/Middle/Upper label series of rock strata. The ordinal meaning remains, but the globally fixed boundaries differ from historic local schemes.
Further historical context
*Original use.* The middle part of Ordovician time as part of the threefold period subdivision, with the named stages Dapingian, Darriwilian.
*Historical problem.* Geologists needed consistent time-series divisions rather than conflicting provincial rock-based subdivisions of the Ordovician.
*Evolution.* Early/Middle/Late label epochs in time; equivalent Lower/Middle/Upper label series of rock strata. The ordinal meaning remains, but the globally fixed boundaries differ from historic local schemes.
Editorial qualification
Not an independently coined etymological name. The ICS chart labels the rock-series Middle; in time, the epoch is Middle Ordovician.
Related names
Sources
- ICS International Chronostratigraphic Chart, 2026/06 — Current nomenclature, rank and numerical age
- ICS Ordovician subdivisions — International epoch/series terminology and constituent stages
- Global historical standardisation of period subdivisions — Historical naming, original claim or scholarly review; see confidence note