Sorting (sediment)
Degree to which sediment grains are concentrated within a narrow or broad range of sizes.
Language and route: English ordinary noun from sort, retained in quantitative sedimentology. English ordinary noun from sort, retained in quantitative sedimentology
Literal gloss: separation by size
The name and its history
First geological naming act not verified · Ordinary English sorting adapted to geology; no verified first use
- What does the word literally mean?
- Immediate borrowing/formation pathway: English ordinary noun from sort, retained in quantitative sedimentology. Linguistic gloss: ‘separation by size’. This is not automatically the original namer’s stated reason.
- What did the original author mean?
- Field descriptions of well- and poorly-sorted deposits predated statistical grain-size distributions; Wentworth’s common classes supported later reproducible measurement and comparison.
- Why was the name needed?
- Grain-size spread could be used to contrast transport regimes and sedimentary environments only if observers agreed on scales and measures.
- What evidence supported the original concept?
- Particle-size distributions and statistical spread derived from sieve, settling or instrument analyses, alongside grain shape and depositional structures.
- How has geology changed the concept?
- Different agents can produce similar sorting; crushing, mixing and diagenesis also complicate measurements. Sorting alone is not a secure environmental diagnosis.
Further historical context
Field descriptions of well- and poorly-sorted deposits predated statistical grain-size distributions; Wentworth’s common classes supported later reproducible measurement and comparison.
Grain-size spread could be used to contrast transport regimes and sedimentary environments only if observers agreed on scales and measures.
Particle-size distributions and statistical spread derived from sieve, settling or instrument analyses, alongside grain shape and depositional structures.
Different agents can produce similar sorting; crushing, mixing and diagenesis also complicate measurements. Sorting alone is not a secure environmental diagnosis.
Editorial qualification
First coinage/priority not independently established; historical narrative is a source-bounded reconstruction.
Related names
Sandstone · Conglomerate · Diamictite · Graded bedding · Imbrication
Sources
- Wentworth (1922), A Scale of Grade and Class Terms for Clastic Sediments — Original 1922 classification paper, verified title/DOI and journal pagination; full article not transcribed
- British Geological Survey, Rock Classification Scheme, Volume 3 overview — Modern descriptive sedimentary classification; does not establish historical first use
- Hybrid event beds and the greywacke problem revisited (2022) — Retrospective of historical matrix/composition schemes and later debate