1
The Solid Phase of Marine Sediments
22
Fig. 1.18 Relative distribution of chlorite in the world ocean, concentration in the carbonate-free < 2 µm size
fraction (from Windom 1976).
Table 1.7 Sedimentation rates of red clay in various
deep-sea basins of the world ocean (data from various
sources, e.g. Berger 1974, Gross 1987).
the pattern of kaolinite. Although chlorite is distributed homogeneously over the oceans, its highest concentration is measured in polar regions and
therefore is referred to as the “high latitude
mineral” (Griffin et al. 1968).
1.4.4
Sedimentation Rates
As can be seen in Table 1.8, the sedimentation
rates of typical types of deep-sea sediments show
a strong geographical variability which is based
on the regionally unsteady import of terrigenous
material and a highly variable biogenic productivity in the ocean.
Basically, it can be stated that the sedimentation rate decreases with increasing distance from a
sediment source, may this either be a continent or
an area of high biogenic productivity. The highest
rates of terrigenous mud formation are recorded
on the shelf off river mouth’s and on the
continental slope, where sedimentation rates can
amount up to several meters per one thousand
years. Distinctly lower values are observed at detritus-starved continental margins, for example of
Antarctica. The lowest sedimentation rates ever
recorded lie between 1 and 3 mm ky -1 . and are
connected to deep-sea red clay in the offshore
deep-sea basins (Table 1.7), especially in the central Pacific Ocean.
Calcareous biogenic oozes demonstrate intermediate rates which frequently lie between 10
and 40 mm ky -1 . Their distribution pattern depends on the biogenic production and on the water depth, or the depth of the CCD. As yet, rate
values between 2 and 10 mm ky -1 . were considered as normal for the sedimentation of siliceous oozes. Recent investigations in the region
of the Antarctic Circumpolar Current have revealed that a very high biogenic production, in
connection with lateral advection and “sediment
focusing”, can even give rise to sedimentation
rates of more than 750 mm per thousand years
(Fig. 1.19).
Rate (mm ky
-1
)
Mean
Range
North Atlantic
1,8
0.5-6.2
South Atlantic
1,9
0.2-7.5
North Pacific
1,5
0.4-6.0
South Pacific
0,45
0.3-0.6
The Solid Phase of Marine Sediments
22
Fig. 1.18 Relative distribution of chlorite in the world ocean, concentration in the carbonate-free < 2 µm size
fraction (from Windom 1976).
Table 1.7 Sedimentation rates of red clay in various
deep-sea basins of the world ocean (data from various
sources, e.g. Berger 1974, Gross 1987).
the pattern of kaolinite. Although chlorite is distributed homogeneously over the oceans, its highest concentration is measured in polar regions and
therefore is referred to as the “high latitude
mineral” (Griffin et al. 1968).
1.4.4
Sedimentation Rates
As can be seen in Table 1.8, the sedimentation
rates of typical types of deep-sea sediments show
a strong geographical variability which is based
on the regionally unsteady import of terrigenous
material and a highly variable biogenic productivity in the ocean.
Basically, it can be stated that the sedimentation rate decreases with increasing distance from a
sediment source, may this either be a continent or
an area of high biogenic productivity. The highest
rates of terrigenous mud formation are recorded
on the shelf off river mouth’s and on the
continental slope, where sedimentation rates can
amount up to several meters per one thousand
years. Distinctly lower values are observed at detritus-starved continental margins, for example of
Antarctica. The lowest sedimentation rates ever
recorded lie between 1 and 3 mm ky -1 . and are
connected to deep-sea red clay in the offshore
deep-sea basins (Table 1.7), especially in the central Pacific Ocean.
Calcareous biogenic oozes demonstrate intermediate rates which frequently lie between 10
and 40 mm ky -1 . Their distribution pattern depends on the biogenic production and on the water depth, or the depth of the CCD. As yet, rate
values between 2 and 10 mm ky -1 . were considered as normal for the sedimentation of siliceous oozes. Recent investigations in the region
of the Antarctic Circumpolar Current have revealed that a very high biogenic production, in
connection with lateral advection and “sediment
focusing”, can even give rise to sedimentation
rates of more than 750 mm per thousand years
(Fig. 1.19).
Rate (mm ky
-1
)
Mean
Range
North Atlantic
1,8
0.5-6.2
South Atlantic
1,9
0.2-7.5
North Pacific
1,5
0.4-6.0
South Pacific
0,45
0.3-0.6