Table 2. Sediment classification by particle size. 





Phi 



Millimeters 



Gravel 



-6.0 to 0.0 



64.0 to 1.0 



Sand 



0.0 to 4.0 



1.0 to 0.0625 



Silt 



4.0 to 8.0 



0.0625 to 0.0039 



Clay 



>8.0 



<0.0039 



Table 3. Classification of sediment sorting by standard 

 deviations (after Folk, 1964). 



Standard Deviation 



C« 



Classification 



<0.35 





Very well sorted 



0.35 to 0.50 





Well- sorted 



0.50 to 0.71 





Moderately well sorted 



0.71 to 1.0 





Moderately sorted 



1.0 to 2.0 





Poorly sorted 



2.0 to 4.0 





Very poorly sorted 



>4.0 





Extremely poorly sorted 



Table 4. Classification of sediment by skewness 

 (after Folk, 1964). 



Skewness 





Classification 



-1.00 to 



-0.30 



Strongly coarse-skewed 



-0.30 to 



-0.10 



Coarse-skewed 



-0.10 to 



0.10 



Near-symmetrical 



0.10 to 



0.30 



Fine-skewed 



0.30 to 



1.00 



Strongly fine-skewed 



27 



