Conglomerate
Consolidated rock dominated by gravel-sized, mostly rounded clasts, with finer sediment or cement between them.
Language and route: English geological borrowing from Latin conglomerāre, ‘roll together into a ball’, via a historical common-language word. English geological borrowing from Latin conglomerāre, ‘roll together into a ball’, via a historical common-language word
Literal gloss: gathered or rolled together
The name and its history
First geological naming act not verified · First geological printed use not verified
- What does the word literally mean?
- Immediate borrowing/formation pathway: English geological borrowing from Latin conglomerāre, ‘roll together into a ball’, via a historical common-language word. Linguistic gloss: ‘gathered or rolled together’. This is not automatically the original namer’s stated reason.
- What did the original author mean?
- An older general word for an aggregate became a geological category when natural philosophers described rocks containing distinct pebbles. Naming did not require acceptance of a single depositional origin.
- Why was the name needed?
- A durable field distinction was required between rocks built of visibly rounded clasts and those composed of angular broken fragments.
- What evidence supported the original concept?
- Pebble shape, boundaries between clasts and matrix, packing and bedding; hydraulic implications of roundness were developed independently of the word.
- How has geology changed the concept?
- The modern division from breccia emphasises clast rounding rather than guaranteed transport distance; tectonic or other nonstandard settings may also produce conglomeratic appearances.
Further historical context
An older general word for an aggregate became a geological category when natural philosophers described rocks containing distinct pebbles. Naming did not require acceptance of a single depositional origin.
A durable field distinction was required between rocks built of visibly rounded clasts and those composed of angular broken fragments.
Pebble shape, boundaries between clasts and matrix, packing and bedding; hydraulic implications of roundness were developed independently of the word.
The modern division from breccia emphasises clast rounding rather than guaranteed transport distance; tectonic or other nonstandard settings may also produce conglomeratic appearances.
Editorial qualification
First coinage/priority not independently established; historical narrative is a source-bounded reconstruction.
Related names
Breccia · Psephite · Diamictite · Imbrication · Sorting (sediment)
Sources
- British Geological Survey, Rock Classification Scheme, Volume 3 overview — Modern descriptive sedimentary classification; does not establish historical first use
- 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
- USGS, Lithologic classification of geologic map units — Alternative modern operational vocabulary, including mudrocks