Grainstone (carbonate)
A carbonate rock whose grains support one another with little or no depositional carbonate mud.
Language and route: English grain + stone; adopted as taxonomic compound in Dunham (1962). English grain + stone; adopted as taxonomic compound in Dunham (1962)
Literal gloss: grain-supported carbonate stone
The name and its history
Robert J. Dunham (1962 classification) · 1962 original abstract checked
- What does the word literally mean?
- Immediate source or formation: English grain + stone; adopted as taxonomic compound in Dunham (1962). Literal gloss ‘grain-supported carbonate stone’. This linguistic evidence is distinct from claims about the namer’s intentions.
- What did the original author mean?
- Dunham replaced some genetically loaded schemes with a fabric-based classification for rocks that preserve depositional texture.
- Why was the name needed?
- It distinguished high-grain, mud-free texture from the mud-containing packstone and from mud-supported rock.
- What evidence supported the original concept?
- Thin-section contacts between grains and lack of depositional carbonate mud; original 1962 abstract and diagrams state criteria.
- How has geology changed the concept?
- Grainstone is a texture, not proof of one environment or transport process; coarse calcite cement can form after burial.
Further historical context
Dunham replaced some genetically loaded schemes with a fabric-based classification for rocks that preserve depositional texture.
It distinguished high-grain, mud-free texture from the mud-containing packstone and from mud-supported rock.
Thin-section contacts between grains and lack of depositional carbonate mud; original 1962 abstract and diagrams state criteria.
Grainstone is a texture, not proof of one environment or transport process; coarse calcite cement can form after burial.
Editorial qualification
Priority and exact original naming language not independently authenticated; distinguish documented later use from first coinage.
Related names
Packstone (carbonate) · Wackestone (carbonate) · Boundstone · Ooid · Coquina · Limestone
Sources
- Dunham 1962, Classification of Carbonate Rocks According to Depositional Texture, AAPG Memoir 1:108–121 — identified original; author abstract directly inspected
- SEPM Strata, carbonate classification comparing Folk, Dunham and extensions — professional retrospective of distinct schemes and Embry–Klovan 1971 extension
- Folk 1959, Practical Petrographic Classification of Limestones, AAPG Bulletin 43:1–38 — identified original publication; abstract directly inspected, not every page