Tortonian
Fifth Miocene age (11.63–7.246 Ma), named for fossil-bearing marls around Tortona.
Language and route: Italian city name adopted by Karl Mayer’s scientific stratigraphy. Tortona, Piedmont, northern Italy → historical scientific stage-name Tortonian. This is a geographical/eponymic formation, not a Greek life-comparison compound.
Literal gloss: of Tortona
The name and its history
Karl Mayer (Mayer-Eymar) · 1858
- What does the word literally mean?
- of Tortona
- What did the original author mean?
- Mayer applied Tortonian widely, including marine fossil beds at Tortona and Vienna Basin and terrestrial mammal-bearing deposits elsewhere.
- Why was the name needed?
- Attempting to assemble synchronous land and sea sequences into one large young Miocene division created over-broad and contradictory correlations.
- What evidence supported the original concept?
- Marine molluscs plus terrestrial Hipparion-bearing faunas were used; the stages were defined before planktonic and magnetic stratigraphic methods.
- How has geology changed the concept?
- His initial Tortonian was far more extensive than the modern stage; adding the Messinian removed the youngest part. The international lower boundary is now at Monte dei Corvi, Italy.
Further historical context
Mayer applied Tortonian widely, including marine fossil beds at Tortona and Vienna Basin and terrestrial mammal-bearing deposits elsewhere.
Attempting to assemble synchronous land and sea sequences into one large young Miocene division created over-broad and contradictory correlations.
Marine molluscs plus terrestrial Hipparion-bearing faunas were used; the stages were defined before planktonic and magnetic stratigraphic methods.
His initial Tortonian was far more extensive than the modern stage; adding the Messinian removed the youngest part. The international lower boundary is now at Monte dei Corvi, Italy.
Editorial qualification
Do not treat modern Tortonian as exactly Mayer’s original beds; his first stage encompassed younger material subsequently partitioned.
Related names
Neogene · Miocene · Serravallian · Messinian
Sources
- International Commission on Stratigraphy, International Chronostratigraphic Chart v2026/06 — Primary authority for present unit names, hierarchy and boundary ages, not first coinages
- ICS Neogene Subcommission, Tortonian stage historical review (PDF) — Mayer-Eymar’s original broad 1858 Tortonian concept and later truncation after Messinian introduction
- Cita (2009), Mediterranean Neogene stratigraphy: development and evolution through the centuries — Historic Mediterranean stage competition, fossil correlation, and international standardisation
- Reguant (2009), historical geography and names of the Neogene stages, Contributions to Science — Author, year and etymological source table for the standard Neogene stages