Size ranges define limits of classes that are given names in the Wentworth scale (or Udden–Wentworth scale) used in the United States. The Krumbein phi (φ) scale, a modification of the Wentworth scale created by W. C. Krumbein[1] in 1934, is a logarithmic scale computed by the equation
where
is the Krumbein phi scale,
is the diameter of the particle or grain in millimeters (Krumbein and Monk's equation)[2] and
In some schemes, gravel is anything larger than sand (comprising granule, pebble, cobble, and boulder in the table above).
International scaleedit
ISO 14688-1:2017, establishes the basic principles for the identification and classification of soils on the basis of those material and mass characteristics most commonly used for soils for engineering purposes. ISO 14688-1 is applicable to natural soils in situ, similar man-made materials in situ and soils redeposited by people.[3]
ISO 14688-1:2017
Name
Size range (mm)
Size range (approx. in)
Very coarse soil
Large boulder
lBo
>630
>24.8031
Boulder
Bo
200–630
7.8740–24.803
Cobble
Co
63–200
2.4803–7.8740
Coarse soil
Gravel
Coarse gravel
cGr
20–63
0.78740–2.4803
Medium gravel
mGr
6.3–20
0.24803–0.78740
Fine gravel
fGr
2.0–6.3
0.078740–0.24803
Sand
Coarse sand
cSa
0.63–2.0
0.024803–0.078740
Medium sand
mSa
0.2–0.63
0.0078740–0.024803
Fine sand
fSa
0.063–0.2
0.0024803–0.0078740
Fine soil
Silt
Coarse silt
cSi
0.02–0.063
0.00078740–0.0024803
Medium silt
mSi
0.0063–0.02
0.00024803–0.00078740
Fine silt
fSi
0.002–0.0063
0.000078740–0.00024803
Clay
Cl
≤0.002
≤0.000078740
Sortingedit
An accumulation of sediment can also be characterized by the grain size distribution. A sediment deposit can undergo sorting when a particle size range is removed by an agency such as a river or the wind. The sorting can be quantified using the Inclusive Graphic Standard Deviation:[4]
where
is the Inclusive Graphic Standard Deviation in phi units
is the 84th percentile of the grain size distribution in phi units, etc.
The result of this can be described using the following terms:
^Krumbein, W. C. (1934). "Size frequency distributions of sediments". Journal of Sedimentary Petrology. 2 (4). doi:10.1306/D4268EB9-2B26-11D7-8648000102C1865D.
^PetroWiki: Estimating permeability based on grain size
^"ISO 14688-1:2017 – Geotechnical investigation and testing – Identification and classification of soil – Part 1: Identification and description". International Organization for Standardization (ISO).
^Folk, Robert L.; Ward, William C. (1957). (PDF). Journal of Sedimentary Petrology. 27 (1): 3–26. Bibcode:1957JSedR..27....3F. doi:10.1306/74d70646-2b21-11d7-8648000102c1865d. Archived from the original (PDF) on 12 May 2014. Retrieved 11 May 2014.
External linksedit
R D Dean & R A Dalrymple, Coastal Processes with Engineering Applications (Cambridge University Press, 2002)
W C Krumbein & L L Sloss, Stratigraphy and Sedimentation, 2nd edition (Freeman, San Francisco, 1963).
Udden, J. A. (1914). "Mechanical composition of clastic sediments". Geological Society of America Bulletin. 25 (1): 655–744. Bibcode:1914GSAB...25..655U. doi:10.1130/GSAB-25-655.
Wentworth, C. K. (1922). "A Scale of Grade and Class Terms for Clastic Sediments". The Journal of Geology. 30 (5): 377–392. Bibcode:1922JG.....30..377W. doi:10.1086/622910. JSTOR 30063207. S2CID 128682870.
February 15, 2024
grain, size, confused, with, crystallite, size, which, referred, grain, sizes, metallurgists, this, article, includes, list, general, references, lacks, sufficient, corresponding, inline, citations, please, help, improve, this, article, introducing, more, prec. Not to be confused with crystallite size which is referred to as grain sizes by metallurgists This article includes a list of general references but it lacks sufficient corresponding inline citations Please help to improve this article by introducing more precise citations July 2011 Learn how and when to remove this template message Grain size or particle size is the diameter of individual grains of sediment or the lithified particles in clastic rocks The term may also be applied to other granular materials This is different from the crystallite size which refers to the size of a single crystal inside a particle or grain A single grain can be composed of several crystals Granular material can range from very small colloidal particles through clay silt sand gravel and cobbles to boulders GranulometryBasic conceptsParticle size Grain size Size distribution MorphologyMethods and techniquesMesh scale Optical granulometry Sieve analysis Soil gradationRelated conceptsGranulation Granular material Mineral dust Pattern recognition Dynamic light scatteringvteWentworth grain size chart from United States Geological Survey Open File Report 2006 1195 Note size typos 33 1mm is 38 1 amp 545mm is 594Beach cobbles at Nash Point South Wales Contents 1 Krumbein phi scale 2 International scale 3 Sorting 4 See also 5 References 6 External linksKrumbein phi scale editSize ranges define limits of classes that are given names in the Wentworth scale or Udden Wentworth scale used in the United States The Krumbein phi f scale a modification of the Wentworth scale created by W C Krumbein 1 in 1934 is a logarithmic scale computed by the equation f log 2 D D 0 displaystyle varphi log 2 frac D D 0 nbsp where f displaystyle varphi nbsp is the Krumbein phi scale D displaystyle D nbsp is the diameter of the particle or grain in millimeters Krumbein and Monk s equation 2 and D 0 displaystyle D 0 nbsp is a reference diameter equal to 1 mm to make the equation dimensionally consistent This equation can be rearranged to find diameter using f D D 0 2 f displaystyle D D 0 cdot 2 varphi nbsp f scale Size range metric Size range approx inches Aggregate name Wentworth class Other names lt 8 gt 256 mm gt 10 1 in Boulder 6 to 8 64 256 mm 2 5 10 1 in Cobble 5 to 6 32 64 mm 1 26 2 5 in Very coarse gravel Pebble 4 to 5 16 32 mm 0 63 1 26 in Coarse gravel Pebble 3 to 4 8 16 mm 0 31 0 63 in Medium gravel Pebble 2 to 3 4 8 mm 0 157 0 31 in Fine gravel Pebble 1 to 2 2 4 mm 0 079 0 157 in Very fine gravel Granule0 to 1 1 2 mm 0 039 0 079 in Very coarse sand1 to 0 0 5 1 mm 0 020 0 039 in Coarse sand2 to 1 0 25 0 5 mm 0 010 0 020 in Medium sand3 to 2 125 250 mm 0 0049 0 010 in Fine sand4 to 3 62 5 125 mm 0 0025 0 0049 in Very fine sand8 to 4 3 9 62 5 mm 0 00015 0 0025 in Silt Mud10 to 8 0 98 3 9 mm 3 8 10 5 0 00015 in Clay Mud20 to 10 0 95 977 nm 3 8 10 8 3 8 10 5 in Colloid MudIn some schemes gravel is anything larger than sand comprising granule pebble cobble and boulder in the table above International scale editISO 14688 1 2017 establishes the basic principles for the identification and classification of soils on the basis of those material and mass characteristics most commonly used for soils for engineering purposes ISO 14688 1 is applicable to natural soils in situ similar man made materials in situ and soils redeposited by people 3 ISO 14688 1 2017 Name Size range mm Size range approx in Very coarse soil Large boulder lBo gt 630 gt 24 8031Boulder Bo 200 630 7 8740 24 803Cobble Co 63 200 2 4803 7 8740Coarse soil Gravel Coarse gravel cGr 20 63 0 78740 2 4803Medium gravel mGr 6 3 20 0 24803 0 78740Fine gravel fGr 2 0 6 3 0 078740 0 24803Sand Coarse sand cSa 0 63 2 0 0 024803 0 078740Medium sand mSa 0 2 0 63 0 0078740 0 024803Fine sand fSa 0 063 0 2 0 0024803 0 0078740Fine soil Silt Coarse silt cSi 0 02 0 063 0 00078740 0 0024803Medium silt mSi 0 0063 0 02 0 00024803 0 00078740Fine silt fSi 0 002 0 0063 0 000078740 0 00024803Clay Cl 0 002 0 000078740Sorting editAn accumulation of sediment can also be characterized by the grain size distribution A sediment deposit can undergo sorting when a particle size range is removed by an agency such as a river or the wind The sorting can be quantified using the Inclusive Graphic Standard Deviation 4 s I ϕ 84 ϕ 16 4 ϕ 95 ϕ 5 6 6 displaystyle sigma I frac phi 84 phi 16 4 frac phi 95 phi 5 6 6 nbsp where s I displaystyle sigma I nbsp is the Inclusive Graphic Standard Deviation in phi units ϕ 84 displaystyle phi 84 nbsp is the 84th percentile of the grain size distribution in phi units etc The result of this can be described using the following terms Diameter phi units Descriptions I displaystyle sigma I nbsp lt 0 35 very well sorted0 35 lt s I displaystyle sigma I nbsp lt 0 50 well sorted0 50 lt s I displaystyle sigma I nbsp lt 1 00 moderately sorted1 00 lt s I displaystyle sigma I nbsp lt 2 00 poorly sorted2 00 lt s I displaystyle sigma I nbsp lt 4 00 very poorly sorted4 00 lt s I displaystyle sigma I nbsp extremely poorly sortedSee also editDeposition geology Feret diameter Martin diameter Orders of magnitude volume Soil texture Substrate biology Unified Soil Classification System USCS References edit Krumbein W C 1934 Size frequency distributions of sediments Journal of Sedimentary Petrology 2 4 doi 10 1306 D4268EB9 2B26 11D7 8648000102C1865D PetroWiki Estimating permeability based on grain size ISO 14688 1 2017 Geotechnical investigation and testing Identification and classification of soil Part 1 Identification and description International Organization for Standardization ISO Folk Robert L Ward William C 1957 Brazos River bar a study in the significance of grain size parameters PDF Journal of Sedimentary Petrology 27 1 3 26 Bibcode 1957JSedR 27 3F doi 10 1306 74d70646 2b21 11d7 8648000102c1865d Archived from the original PDF on 12 May 2014 Retrieved 11 May 2014 External links editR D Dean amp R A Dalrymple Coastal Processes with Engineering Applications Cambridge University Press 2002 W C Krumbein amp L L Sloss Stratigraphy and Sedimentation 2nd edition Freeman San Francisco 1963 Udden J A 1914 Mechanical composition of clastic sediments Geological Society of America Bulletin 25 1 655 744 Bibcode 1914GSAB 25 655U doi 10 1130 GSAB 25 655 Wentworth C K 1922 A Scale of Grade and Class Terms for Clastic Sediments The Journal of Geology 30 5 377 392 Bibcode 1922JG 30 377W doi 10 1086 622910 JSTOR 30063207 S2CID 128682870 Retrieved from https en wikipedia org w index php title Grain size amp oldid 1178259988, wikipedia, wiki, book, books, library,