Micrite
Very fine carbonate mud or microcrystalline carbonate material, frequently serving as limestone matrix.
Language and route: English scientific contraction microcrystalline calcite; coined/defined in Folk (1959), not a whole Greek noun. English scientific contraction microcrystalline calcite; coined/defined in Folk (1959), not a whole Greek noun
Literal gloss: MICRocrystalline calcITE
The name and its history
Robert L. Folk (classification and term in 1959) · 1959 publication abstract and pagination checked
- What does the word literally mean?
- Immediate source or formation: English scientific contraction microcrystalline calcite; coined/defined in Folk (1959), not a whole Greek noun. Literal gloss ‘MICRocrystalline calcITE’. This linguistic evidence is distinct from claims about the namer’s intentions.
- What did the original author mean?
- Folk contrasted extremely fine calcite “ooze” with transported allochem grains and coarser sparry pore cement in thin sections.
- Why was the name needed?
- Earlier limestone categories blurred carbonate mud with recrystallised cement; new compounds supported more interpretable petrographic descriptions.
- What evidence supported the original concept?
- One-to-four-micrometre calcite matrix in Folk’s 1959 abstract; grain and cement relationships and later crystal-growth studies challenge simple origin stories.
- How has geology changed the concept?
- Micrite need not preserve original depositional mud unaltered, and the term can encompass various microcrystalline carbonate products.
Further historical context
Folk contrasted extremely fine calcite “ooze” with transported allochem grains and coarser sparry pore cement in thin sections.
Earlier limestone categories blurred carbonate mud with recrystallised cement; new compounds supported more interpretable petrographic descriptions.
One-to-four-micrometre calcite matrix in Folk’s 1959 abstract; grain and cement relationships and later crystal-growth studies challenge simple origin stories.
Micrite need not preserve original depositional mud unaltered, and the term can encompass various microcrystalline carbonate products.
Editorial qualification
Priority and exact original naming language not independently authenticated; distinguish documented later use from first coinage.
Related names
Sparite · Allochem · Limestone · Grainstone (carbonate) · Wackestone (carbonate) · Packstone (carbonate)
Sources
- Folk 1959, Practical Petrographic Classification of Limestones, AAPG Bulletin 43:1–38 — identified original publication; abstract directly inspected, not every page
- SEPM Strata, carbonate classification comparing Folk, Dunham and extensions — professional retrospective of distinct schemes and Embry–Klovan 1971 extension
- British Geological Survey, Rock Classification Scheme, vol. 3 — modern descriptive classification, not evidence of historical first coinage