Sedimentary Rocks (Extra - Udden-Wentworth Scale, Provenances, Pettijohn and Mudrock Classification Flashcards
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Size range for Boulder
> 256mm
Size range for Cobble
64-256 mm
Size range for Pebble
4-64 mm
Size range for Granule
2-4 mm
Size range for Sand
0.063-2 mm or 1/16-2 mm
Size range for Silt
0.0039-0.063 mm or 1/256-1/16 mm
Size range for Clay
<1/256 mm
Phi value for Boulders
< -8
Phi value for Cobbles
-4 to -8
Phi value for Pebbles
-2 to -4
Phi value for Granules
-1 to -2
Phi value for Very coarse sand
0 to -1
Phi value for Coarse sand
1 to 0
Phi value for Medium sand
2 to 1
Phi value for Fine sand
3 to 2
Phi value for Very fine sand
4 to 3
Phi value for Coarse silt
5 to 4
Phi value for Medium silt
6 to 5
Phi value for fine silt
7 to 6
Phi value for Very fine silt
8 to 7
Phi value for Clay
> 8
Common name for Boulder, Cobble, Pebble and Granule
Gravel
What rocks are in gravelstones?
Conglomerate and Breccia
What rocks are in Sandstones?
Sandstone (Arkose, Wacke, Graywacke)
What rocks are in Mudrock?
Siltstone and claystone
Per cent matrix for Arenite in Pettijohn
0-15%
Per cent matrix for Wacke in Pettijohn
15-75%
Per cent matrix for Mudrock in Pettijohn
75-100%
Sand size in Mudrock Classification
> 62 μm (micrometer)
Clay size in Mudrock Classification
<4 μm (micrometer)
Silt size in Mudrock Classification
4-62 μm (micrometer)