Unformatted text preview: o f = roughness factor — particle size in channel; dictates how fast the water will move 0 s = slope of channel 0 Morphology of Grains (shape) 0 Roundness
0 Form 0 Surface texture I Roundness — how smooth or angularity of particle surface 0 Power’s Scale —- visual scale
0 Wadell Scale — Rw = DJD;
0 Short vs. Intermediate vs. Long 0 Orientate grain so that s-side is facing you 0' Particles only at pebble size should be measured I Sphericity — to combat roundness errors; combat rod shape grains because Di=Dc 0:621) . '11,, = 3«J[sz/(L*I)] 0 The closer you get to a perfect sphere and cube, the closer you get tol I Form — equate vs. disc vs. rod I Surface Texture — microstructure -. I Frosted grain surface 0 Produced artiﬁcially by chemically etching or sand blasting
surface Same thing happens naturally by grains striking each other Almost exclusive to Eollian environment Dose not happen in water because water acts like a cushion
Water also has a higher density than air causing velocities of grains to slow I Ventifact * sculptured gravel . - Windblown sediment chips away gravel surface ...
View Full Document
- Spring '11