Udden Grade Scale

sedimentology

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July 14, 2026

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The Udden Grade Scale, adapted by Wentworth, is a system in sedimentology used to categorize particle sizes into discrete groups. This scale standardizes terminology for sediments like clay, silt, and sand, aiding statistical analysis. It's a geometric scale where each size grade has a constant ratio to the next, making it suitable for describing sediments across different particle sizes. The scale is crucial for understanding the transportation, sorting, and deposition of sediments, offering clues about their history.12

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sedimentary rock
Grain size
This millimetre, or Udden-Wentworth, scale is a geometric grain-size scale since there is a constant ratio between class limits. Such a scheme is well suited for the description of sediments because it gives equal significance to size ratios, whether they relate to gravel, sand, silt, or clay. The…
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This millimetre, or Udden-Wentworth, scale is a geometric grain-size scale since there is a constant ratio between class limits. Such a scheme is well suited for the description of sediments because it gives equal significance to size ratios, whether they relate to gravel, sand, silt, or clay. The…
Read More

grain size scale
Udden was adapted (1922) by C.K. Wentworth, who expanded the definitions of the various grades to conform with actual usage by researchers; most sedimentologists have adopted the Udden scale with the Wentworth modifications.
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Udden was adapted (1922) by C.K. Wentworth, who expanded the definitions of the various grades to conform with actual usage by researchers; most sedimentologists have adopted the Udden scale with the Wentworth modifications.
Read More