Geology Reference
In-Depth Information
a
b
1.6
2.0
1.6
1.2
1.2
0.8
0.8
0.4
0.4
BD
w
= 0.6924275 + 1.2904878e
(-M%/103.5056922)
BD
d
= 0.7955892 + 2.3863045e
(-M%/125.8292772)
(R = 0.9761, n = 337)
(R = 0.9847, n = 337)
0.0
0.0
0
20
40
60
80
100
0
20
40
60
80
100
Mud content (dry weight-%)
Mud content (dry weight-%)
Fig. 10.10
Relationship between mud content and wet (
a
) and dry (
b
) bulk densities in Wadden Sea sediments (Based on Flemming
and Delafontaine
2000
)
between absolute and relative water contents, the
former being defined as the ratio between the mass of
pore water and the mass of the total water-saturated
sample, the latter as the ratio between the mass of pore
water and the mass of the dry solids. Relative water
content can reach several hundred percent, i.e. the
mass of the water can greatly exceed the mass of the
dry solids, whereas the absolute water content is always
a fraction of one-hundred. Relative water content
<100% can therefore be confused with absolute con-
tent if not identified as such. Excellent treatments of
these and other mass physical properties can be found
in Lambe and Whitman (
1969
), Carver (
1971
),
Inderbitzen (
1974
), Dunn et al. (
1980
), Hillel (
1998
),
and Warrick (
2002
).
Mass concentrations of sand and mud relative to
the total sediment (sand + mud) are illustrated in
Fig.
10.12a
. Of particular interest here is the counter-
intuitive trend described by the dry mass concentration
of the mud component (Fig.
10.12b
). Thus, with
increasing mud content, the mass concentration of
mud initially increases as would intuitively be expected.
At higher mud content, however, the trend changes in
an unexpected manner, i.e. it flattens off, peaks (in this
case at a mud content of about 60%), and thereafter
decreases again. This counter-intuitive trend is caused
by a progressive change in the network structure or
fabric of the sediment as the water content increases
with increasing mud content. Beyond the apex of the
Fig. 10.11
Relationship between dry bulk density and absolute
water content in intertidal sediments of the Wadden Sea (Based
on Flemming and Delafontaine
2000
). Note the very high
correlation. The relationship has universal character for average
terrigenous material
As can be seen, the correlation is superior to that for
mud content (Fig.
10.10b
) and, for average terrigenous
material (G = 2.65 g cm
−3
), this relationship has uni-
versal character (cf. regression equation in Fig.
10.11
).
It is important, however, to carefully distinguish
