Biogenic Barium as a Proxy for Paleoproductivity
361
Outlook
Today, the use of biogenic barium as a tool for the
reconstruction of paleoproductivity is a well-established method. The compilation of additional data
from sediment traps and surface sediment samples
will certainly improve quantitative calculations.
Recent investigations show that not only the amount
of marine barite, but also its composition can be
used for paleoceanographic interpretations (Paytan
et al. 1993). Sulfur-isotopes have been utilized for
early diagenetic studies (Torres et al. 1996). Discrete barite particles incorporate a number of minor and trace elements of oceanographic interest,
for example Sr, Ca, Ra, U, Pb and the rare-earth
elements. Thus if the difficulty of isolating a fraction of pure marine barite can be mastered, it may
be possible to monitor a variety of oceanographic
processes in this single phase, as there are: the seawater Sr/Ca ratio (Paytan et al. 1993), important
for evaluating the degree of carbonate diagenesis
and for understanding and modelling the seawater
Sr isotope curve with respect to the sinks, sources
and size of the oceanic Sr reservoir; the sea-water Ba/Ca ratio important for paleo-alkalinity studies and the Nd isotope ratios (Paytan et al. 1992)
which are important for paleocirculation studies.
The strontium isotope composition of seawater has
been successfully reconstructed from barites
(Paytan et al. 1993). This approach is especially
useful where diagenesis of carbonates has destroyed the information in this phase. Barite with
its low solubility provides an effective alternative
in these cases. Efforts continue to utilize other trace
elements. The main problem to be overcome consists in the development of a leaching procedure,
which permits the purification of the marine barite
especially from areas of high terrigenous input.
Acknowledgments
We thank the crews and masters of research vessels FS METEOR and FS POLARSTERN for
their help in coring and sampling operations during
numerous cruises in the South Atlantic. P. Muller,
R. Schneider and C. Ruhlemann kindly provided
unpublished data on organic carbon. We are also
indebted to R. Haese for processing of surface sampies from the central Atlantic. The constructive and
helpful reviews of A. Paytan and G. De Lange
greatly improved the manuscript. Research in the
Polar Frontal Zone and acquisition of surface
sample data in the Southern Ocean was
supported by G. Bohrmann (GEOMAR) under
DFG-grant Bo 1049. This research was funded
by the Deutsche Forschungsgemeinschaft
(Sonder-forschungsbereich 261 at Bremen University, Contribution No. 206). Data are available
under www.pangaea.delProjects/SFB261.
References
Andel TH van, Heath GR, Moore TC (1975) Cenozoic
history and paleoceanography of the central equatorial Pacific Ocean. Geol Soc Amer Memoir 143:
1-134
BamolaJM, RaynaudD, Korotkevich YS, Lorius C (1987)
Vostok ice core provides 160,000-year record of atmosphericCO,. Nature 329: 408-414
Berger WH, Smetacek VS, Wefer G (1989) Ocean productivity and paleoproductivity - An overview. In:
Berger WH, Smetacek VS, Wefer G (eds) Productivity of the Ocean: Present and Past. Springer, Berlin
HeidelbergNewYork,pp 1-34
Berner W, Stouffer B, Oeschger H (1979) Past atmospheric composition and climate, gas parameters
measured on ice cores. Nature 275: 53-65
Bernstein RE, Byrne RH, Betzer PR, Greco AM (1992)
Morphologies and transformations of celestite in
seawater: The role of acantharians in strontium and
barium geochemistry. Geochim Cosmochim Acta 56:
3273-3279
Bickert T (1992) Rekonstruction der spiitquartiiren
Bodenwasserzirku1ation im ostlichen Siidatlantik
tiber stabile Isotope benthischer Foraminiferen. Ber
Fachber Geowiss Univ Bremen 27, pp 1-205
Bishop JKB (1988) The barite-opal-organic carbon association in oceanic particulate matter. Nature 332:
341-343
Bonn WJ (1995) Biogenopal und biogenes Barium als
Indikatoren flir spatquartare Produktivitatsanderungen am antarktischen Kontinentalhang,
atlantischer Sektor. Ber Polarforsch Bremerhaven
180,pp 1-186
Bonn WJ, Gingele FX, Grobe H, Mackensen A, FUtterer
DK (1998) Paleoproductivity at the Antarctic continental margin: opal and barium records of the last
400 kyr. Paleogeogr Paleoc1imatol Paleoecol139:
195-211
361
Outlook
Today, the use of biogenic barium as a tool for the
reconstruction of paleoproductivity is a well-established method. The compilation of additional data
from sediment traps and surface sediment samples
will certainly improve quantitative calculations.
Recent investigations show that not only the amount
of marine barite, but also its composition can be
used for paleoceanographic interpretations (Paytan
et al. 1993). Sulfur-isotopes have been utilized for
early diagenetic studies (Torres et al. 1996). Discrete barite particles incorporate a number of minor and trace elements of oceanographic interest,
for example Sr, Ca, Ra, U, Pb and the rare-earth
elements. Thus if the difficulty of isolating a fraction of pure marine barite can be mastered, it may
be possible to monitor a variety of oceanographic
processes in this single phase, as there are: the seawater Sr/Ca ratio (Paytan et al. 1993), important
for evaluating the degree of carbonate diagenesis
and for understanding and modelling the seawater
Sr isotope curve with respect to the sinks, sources
and size of the oceanic Sr reservoir; the sea-water Ba/Ca ratio important for paleo-alkalinity studies and the Nd isotope ratios (Paytan et al. 1992)
which are important for paleocirculation studies.
The strontium isotope composition of seawater has
been successfully reconstructed from barites
(Paytan et al. 1993). This approach is especially
useful where diagenesis of carbonates has destroyed the information in this phase. Barite with
its low solubility provides an effective alternative
in these cases. Efforts continue to utilize other trace
elements. The main problem to be overcome consists in the development of a leaching procedure,
which permits the purification of the marine barite
especially from areas of high terrigenous input.
Acknowledgments
We thank the crews and masters of research vessels FS METEOR and FS POLARSTERN for
their help in coring and sampling operations during
numerous cruises in the South Atlantic. P. Muller,
R. Schneider and C. Ruhlemann kindly provided
unpublished data on organic carbon. We are also
indebted to R. Haese for processing of surface sampies from the central Atlantic. The constructive and
helpful reviews of A. Paytan and G. De Lange
greatly improved the manuscript. Research in the
Polar Frontal Zone and acquisition of surface
sample data in the Southern Ocean was
supported by G. Bohrmann (GEOMAR) under
DFG-grant Bo 1049. This research was funded
by the Deutsche Forschungsgemeinschaft
(Sonder-forschungsbereich 261 at Bremen University, Contribution No. 206). Data are available
under www.pangaea.delProjects/SFB261.
References
Andel TH van, Heath GR, Moore TC (1975) Cenozoic
history and paleoceanography of the central equatorial Pacific Ocean. Geol Soc Amer Memoir 143:
1-134
BamolaJM, RaynaudD, Korotkevich YS, Lorius C (1987)
Vostok ice core provides 160,000-year record of atmosphericCO,. Nature 329: 408-414
Berger WH, Smetacek VS, Wefer G (1989) Ocean productivity and paleoproductivity - An overview. In:
Berger WH, Smetacek VS, Wefer G (eds) Productivity of the Ocean: Present and Past. Springer, Berlin
HeidelbergNewYork,pp 1-34
Berner W, Stouffer B, Oeschger H (1979) Past atmospheric composition and climate, gas parameters
measured on ice cores. Nature 275: 53-65
Bernstein RE, Byrne RH, Betzer PR, Greco AM (1992)
Morphologies and transformations of celestite in
seawater: The role of acantharians in strontium and
barium geochemistry. Geochim Cosmochim Acta 56:
3273-3279
Bickert T (1992) Rekonstruction der spiitquartiiren
Bodenwasserzirku1ation im ostlichen Siidatlantik
tiber stabile Isotope benthischer Foraminiferen. Ber
Fachber Geowiss Univ Bremen 27, pp 1-205
Bishop JKB (1988) The barite-opal-organic carbon association in oceanic particulate matter. Nature 332:
341-343
Bonn WJ (1995) Biogenopal und biogenes Barium als
Indikatoren flir spatquartare Produktivitatsanderungen am antarktischen Kontinentalhang,
atlantischer Sektor. Ber Polarforsch Bremerhaven
180,pp 1-186
Bonn WJ, Gingele FX, Grobe H, Mackensen A, FUtterer
DK (1998) Paleoproductivity at the Antarctic continental margin: opal and barium records of the last
400 kyr. Paleogeogr Paleoc1imatol Paleoecol139:
195-211