Quaternary
Youngest Cenozoic period, comprising Pleistocene and Holocene.
Language and route: French Quaternaire, ultimately Latin ordinal vocabulary. French Quaternaire introduced in a geological sense in 1829; Latin quārtus, ‘fourth’, supplies its ordinal meaning.
Literal gloss: fourth
The name and its history
Jules Desnoyers (word); Arduino (earlier ordinal scheme) · 1829; 1759 antecedent
- What does the word literally mean?
- The ‘fourth’ is a remnant of older divisions in which Primary, Secondary, Tertiary and a fourth order were distinguished.
- What did the original author mean?
- ‘Fourth’ comes from ordinal rock classifications preceding modern fossil and time-based schemes.
- Why was the name needed?
- Younger deposits were being distinguished from older ‘Tertiary’ terrain amid new evidence for former climate and humans.
- What evidence supported the original concept?
- Superposition and distinctive surficial deposits, later joined by evidence of glaciation, were central to the nineteenth-century concept.
- How has geology changed the concept?
- The present Quaternary is a formal period with a base at 2.58 Ma; ‘fourth’ has no literal connection to four current ICS periods.
Further historical context
Giovanni Arduino wrote in 1759 of four geological ‘orders’ of strata in northern Italy, but specialist histories caution that he did not literally use the later word Quaternario. Jules Desnoyers’s 1829 Quaternaire was applied to recent deposits, before Pleistocene glaciation gained its modern explanatory status.
The Quaternary became associated with drift, former glaciers and the human past. Nineteenth- and twentieth-century debates repeatedly questioned its scientific rank and whether it should be subsumed within Neogene. The ICS retained the Quaternary, and its lower boundary was revised to 2.58 Ma in 2009.
Editorial qualification
Arduino’s fourth order must not be represented as his first printed use of the exact word Quaternary.
Related names
Neogene · Cenozoic · Tertiary · Superposition · Gelasian · Pleistocene · Holocene · Anthropocene
Sources
- ICS International Chronostratigraphic Chart, 2026/06 — Current name, rank and numerical boundaries
- ICS Subcommission: History of Quaternary nomenclature — Primary/Secondary/Tertiary/Quaternary; historical interpretation
- Gibbard & Head (2009), Quaternary definition and nomenclature — Quaternary restoration and historical nuance
- Berggren et al. (2008), The Neogene: origin, adoption, evolution, and controversy — Historiography of Hörnes and Neogene–Quaternary dispute