1
The Solid Phase of Marine Sediments
18
(Table 1.5). The distribution of these sediments in
the three great oceans shows a considerable degree of variation (Fig. 1.14). The distribution patterns strongly depend on the water depth, i.e. the
position of the CCD. Calcareous ooze, primarily
consisting of foraminiferal oozes and nannoplankton oozes, covers vast stretches of the seafloor at water depths less than 3-4 km and
roughly retraces the contours of the mid-oceanic
ridges as well as other plateaus and islands,
whereas pelagic clay covers the vast deep-sea
plains in the form of deep-sea red clay. This particular pattern is especially obvious in the Atlantic Ocean.
muddy coast
1
2
nearshore
mud-belt
3
4
mid-shelf
mud-belt
outer-shelf
mud-belt
5
mud blanket
(off delta)*
S H E L F
E D G E
* or under advective mud stream
C O A S T
Fig. 1.13 Schematic representation of modern mud accumulation on continental shelves (modified from McCave
(1972)).
Table 1.5 Relative areas of world oceans covered with pelagic sediments; area of deep-sea floor = 268.1·10 6 km 2
(from Berger (1976)).
Sedim ents (%)
Atla ntic
Pacific
India n
W orld
Calcareous ooze
65,1
36,2
54,3
47,1
Pteropod ooze
2,4
0,1
--0,6
Diatom ooze
6,7
10,1
19,9
11,6
Radiolarian ooze
--4,6
0,5
2,6
Red clays
25,8
49,1
25,3
38,1
Relative size of ocean (% )
23,0
53,4
23,6
100,0