Grain Size Flashcards
- A widely used grade scale for expressing particle size
- A logarithmic and geometric scale with a fix ratio between successive elements
Udden-Wentworth Scale
Udden-Wentworth Scale extends from
< 1/256 mm to >256 mm
logarithmic scale for sediment size
Kumbrein Phi Scale
Increase in abs value negative phi =
Increase in mm size
- Increase in positive phi =
decrease in mm size
particles that are settling will pass through a diffracted light, the angle of the diffracted light increases with a decreasing particle size. A detector senses the angular distribution of scattered light energy.
- Laser Diffraction size analyzer
sediments are slowly poured into an electrolyte solution, where sediments will pass through, where changes in the electrical field will produce pulses, translating into the grain size
- Electro-resistant size analysers
Φ < 0.35
VW Sorted
0.35 < Φ < 0.5
W Sorted
0.5 < Φ < 0.7
MW Sorted
0.7 < Φ < 1
M Sorted
1 < Φ <2
P Sorted
2 < Φ <4
VP Sorted
0.4 > Φ
EP Sorted
- based on a constant ratio of two between successive class boundaries together with terms for the classes
- A Geometric Scale
Udden Wentworth Scale
Kumbrein introduced an ?? Measured in ?? uunits
Kumbrein; Phi
clast size of conglomerates and breccias can be measured directly with a ?
tape measure
With poorly cemented sandstones and unconsolidated sands, ???is the most popular technique
sieving
