a
b
c
99
%
90
80
75
70
60
50
40
30
25
20
10
5
1
–3
8
Pebbles
Granules
4
2
Sand
25
75
1
1/2
1/4
1/8 1/16 1/32
6 (phi)
1/64 mm
Silt
–2
–1
0
1
2
3
4
5
100
%
90
80
75
70
60
50
40
30
25
20
10
0
0.002
0.006
0.02
0.06
0.2
0.6
2
6
20 100
a
(So)
(Sk)
–
+
M
Md
O 25
O 75
30
20
10
0
2
%
μ
μ
μ
μ mm mm mm mm mm
6 20 60 0.2 0.6 2
6
20
Fig. 2.3 Presentation of the same grain-size distribution data as
(a) histogram, (b) cumulative curve, and (c) cumulative curve
on probability paper. When plotted on probability paper, a
logarithmic normal distribution, like a Gaussian curve, will
plot as a straight line
2 Introduction to Sedimentology
37