Lesson 2: Grain Size Flashcards
Logarithmic scale for sediment size
Kumbrein Phi Scale
Grade scale for expressing particle size that extends from 1/256 mm to >256mm
Udden-Wentworth Scale
Size of boulder in Phi (f)
-12.0 - -8.0
Size of cobble in Phi (f)
-8.0 - -6.0
Size of pebble in Phi (f)
-6.0 - -2.0
Size of granule in Phi (f)
-2.0 - -1.0
Size of very coarse sand in Phi (f)
-1.0 - 0.0
Size of coarse sand in Phi (f)
0.0 - 1.0
Size of medium sand in Phi (f)
1.0 - 2.0
Size of fine sand in Phi (f)
2.0 - 3.0
Size of very fine sand in Phi (f)
3.0 - 4.0
Size of coarse silt in Phi (f)
4.0 - 5.0
Size of medium silt in Phi (f)
5.0 - 6.0
Size of fine silt in Phi (f)
6.0 - 7.0
Size of very fine silt in Phi (f)
7.0 - 8.0
Size of clay in Phi (f)
8.0 - 14.0
What type of method of analysis is used for unconsolidated boulders, cobbles, and pebbles?
manual measurement of individual clasts
What type of method of analysis is used for unconsolidated granules and sand?
sieving, settling tube analysis, and image analysis
What type of method of analysis is used for unconsolidated silt and clay?
Pipette analysis, sedimentation balances, sedigraph, laser diffractometry, and electro-resistance size analysis
What type of method of analysis is used for lithified boulders, cobbles, and pebbles?
manual measurement of individual clasts
What type of method of analysis is used for lithified granules and sand?
Thin section measurement and image analysis
What type of method of analysis is used for lithified silt and clay?
Electron microscopy
Size of very well sorted in Phi
<0.35
Size of well sorted in Phi
0.35 - 0.50