occurs within a few hundred meters of burial, while
limestones are produced by further cementation
under about 1 km of burial. Although the transformation of ooze to chalk to limestone is the expected
diagenetic sequence, smaller scale reversals in lithification are often observed. Such reversals in pattern
have led to the concept of diagenetic potential,
which simply states that different sediments will
take different lengths of time to reach equal stages
of lithification depending upon the original character of the deposited sediment. Such factors as the
original proportions of coccoliths to foraminifera
(affecting grain size), the amount of dissolution experienced before burial, sedimentation rates, and
numerous other subtle factors can influence the
diagenetic potential of a carbonate sediment. To the
extent that these factors reflect original oceanographic conditions, the sub-bottom acoustic reflectors that result from changing lithification state
and diagenetic potential preserve a history of paleooceanographic events that can often be traced across
large regions within ocean basins.
See also
Carbon Dioxide (CO 2 ) Cycle. Cenozoic Climate –
Oxygen Isotope Evidence. Cenozoic Oceans –
Carbon Cycle Models. Ocean Carbon System,
Modeling of. Pore Water Chemistry.
Further Reading
Archer DE (1996) An atlas of the distribution of calcium
carbonate in sediments of the deep sea. Global
Biogeochemical Cycles 10: 159--174.
Arrhenius G (1988) Rate of production, dissolution and
accumulation of biogenic solids in the ocean.
Palaeogeography,
Palaeoclimatology
and
Palaeoecology 67: 1119--1146.
Berger WH (1976) Biogenous deep sea sediments:
production, preservation and interpretation. In: Riley JP
and Chester R (eds.) Chemical Oceanography, vol. 5,
pp. 266--388. London: Academic Press.
Berger WH and Roth PH (1975) Oceanic micropaleontology: progress and prospect. Reviews of Geophysics
and Space Physics 13: 561--585.
0
10
20
30
40
50
5000
4000
3000
Q Plio.
Miocene
Oligocene
Eocene
South Atlantic (B 75)
Indian (P 92)
Atlantic (V 75)
Indian (S 77)
Nonequatorial Pacific (V 75)
Equatorial Pacific (V 75)
Age (Ma)
Water depth (m)
Figure 6 Compilation of reconstructed variations in the depth of the CCD from selected studies covering the last 50 million years for
different oceanic regions. The overall similarity of the CCD behavior between regions suggests a common forcing mechanism, such as
global sea level or a long-term change in the supply of calcium to the ocean. Variations between the oceans are probably the result of
differences in regional surface productivity and deep circulation patterns. Cited CCD studies include: V75, van Andel (1975); B75,
Berger and Roth (1975); S77, Sclater et al. (1977); P92, Peterson et al. (1992).
344 CALCIUM CARBONATES
limestones are produced by further cementation
under about 1 km of burial. Although the transformation of ooze to chalk to limestone is the expected
diagenetic sequence, smaller scale reversals in lithification are often observed. Such reversals in pattern
have led to the concept of diagenetic potential,
which simply states that different sediments will
take different lengths of time to reach equal stages
of lithification depending upon the original character of the deposited sediment. Such factors as the
original proportions of coccoliths to foraminifera
(affecting grain size), the amount of dissolution experienced before burial, sedimentation rates, and
numerous other subtle factors can influence the
diagenetic potential of a carbonate sediment. To the
extent that these factors reflect original oceanographic conditions, the sub-bottom acoustic reflectors that result from changing lithification state
and diagenetic potential preserve a history of paleooceanographic events that can often be traced across
large regions within ocean basins.
See also
Carbon Dioxide (CO 2 ) Cycle. Cenozoic Climate –
Oxygen Isotope Evidence. Cenozoic Oceans –
Carbon Cycle Models. Ocean Carbon System,
Modeling of. Pore Water Chemistry.
Further Reading
Archer DE (1996) An atlas of the distribution of calcium
carbonate in sediments of the deep sea. Global
Biogeochemical Cycles 10: 159--174.
Arrhenius G (1988) Rate of production, dissolution and
accumulation of biogenic solids in the ocean.
Palaeogeography,
Palaeoclimatology
and
Palaeoecology 67: 1119--1146.
Berger WH (1976) Biogenous deep sea sediments:
production, preservation and interpretation. In: Riley JP
and Chester R (eds.) Chemical Oceanography, vol. 5,
pp. 266--388. London: Academic Press.
Berger WH and Roth PH (1975) Oceanic micropaleontology: progress and prospect. Reviews of Geophysics
and Space Physics 13: 561--585.
0
10
20
30
40
50
5000
4000
3000
Q Plio.
Miocene
Oligocene
Eocene
South Atlantic (B 75)
Indian (P 92)
Atlantic (V 75)
Indian (S 77)
Nonequatorial Pacific (V 75)
Equatorial Pacific (V 75)
Age (Ma)
Water depth (m)
Figure 6 Compilation of reconstructed variations in the depth of the CCD from selected studies covering the last 50 million years for
different oceanic regions. The overall similarity of the CCD behavior between regions suggests a common forcing mechanism, such as
global sea level or a long-term change in the supply of calcium to the ocean. Variations between the oceans are probably the result of
differences in regional surface productivity and deep circulation patterns. Cited CCD studies include: V75, van Andel (1975); B75,
Berger and Roth (1975); S77, Sclater et al. (1977); P92, Peterson et al. (1992).
344 CALCIUM CARBONATES