Biostratigraphy
The subdivision and correlation of stratified rocks by their fossil content, especially characteristic taxa and their distributions.
Language and route: English modern compound bio- + stratigraphy. Greek bíos, ‘life’, combined with mixed-root stratigraphy. The terminology describes a method developed from fossil succession before it was internationally codified.
Literal gloss: life-layer description
The name and its history
Historical method established by multiple geologists; first lexical coiner unverified · Nineteenth-century method; modern codified terminology later
- What does the word literally mean?
- ‘Description of strata using evidence of life’.
- What did the original author mean?
- Fossil-based correlation grew from nineteenth-century observations by William Smith and others; the formal bio- compound reflects the established method and cannot automatically be ascribed to them as coiners.
- Why was the name needed?
- Rock successions can change lithology between localities: fossil succession offered a way to correlate broadly contemporaneous intervals despite differences in rock appearance.
- What evidence supported the original concept?
- Fossil first/last appearances, characteristic assemblages and taxonomic identification. Biozones are evidence-based bodies of strata, not automatically equal-duration global time slices.
- How has geology changed the concept?
- International stratigraphic guides separate biostratigraphic units from lithostratigraphic formations and formal chronostratigraphic stages.
Further historical context
The distinction illuminates the logic behind many Ordovician, Silurian and Devonian stage revisions, which sought more widely correlatable fossil events.
Editorial qualification
Do not equate William Smith’s discovery of fossil succession with proven first use of the word biostratigraphy.
Related names
Lithostratigraphy · Stratigraphy · Fossil · Graptolite · Conodont · Ammonoid
Sources
- ICS International Stratigraphic Guide, Biostratigraphic Units — Definitions and limits of biostratigraphic zones
- Geoscience Australia, Biostratigraphy — Fossil-based correlation and biozone concepts
- Hedberg (1972), International Guide to Stratigraphic Classification — Historical codification of stratigraphic nomenclature