Kaolinite and Chlorite as Tracers of Modern and Late Quaternary
Deep Water Circulation in the South Atlantic
and the Adjoining Southern Ocean
B. Diekmann!', G. Kuhn!, A. Mackensenl,R. Petschick 2 , D.K. Filttererl,
R. Gersonde!, C. Riihlemann 3 and H.-S. Niebler 3
1 Alfred-Wegener-Institutfor Polar- und Meeresforschung, Postfach 12 0161,
D-27515 Bremerhaven, Germany
2 Geologisch-Palaeontologisches Institut, Universitiit Franlifurt,
Senckenberganlage 32-34,
D-60054 FranlifurtlMain, Germany
3Universitiit Bremen, Fachbereich Geowissenschaften, Postfach 330440,
D-28334 Bremen, Germany
*corresponding author (e-mail}:bdiekmann@awi-bremerhaven.de
Abstract: In the South Atlantic and adjoining Southern Ocean the kaolinite/chlorite-ratio in Late
Quaternary sediments are an alternative deep water proxy to benthic foraminiferal proxies and
carbonate preservation indices that is even suitable in regions with poor carbonate preservation.
This paper shows the relationship between modem abyssal circulation and the kaolinite/chloriteratio and presents reconstructions of deep and bottom water advection based on the kaolinite/
chlorite proxy. We also discuss the limitations and future perspectives of the kaolinite/chlorite proxy.
Latitudinal and water depth-related patterns of the kaolinite/chlorite-ratio in surface sediments
correspond to the modem deep and bottom water mass distribution. Kaolinite originates from lowlatitudes and traces North Atlantic Deep Water (northern-source deep water) advection to the
south. Chlorite from the southern high-latitudes is exported via northward advecting Antarctic
Bottom Water and Circumpolar Deep Water (southern-source deep and bottom water). Deep-sea
sedimentation in regions underlying the Antarctic Circumpolar Current was current-dominated
throughout the Late Quaternary. Temporal variations of the kaolinite/chlorite-ratio in response to
glacial-interglacial cycles reflect changing deep water mass configurations, suggesting a shallowing
and northward retreat of northern-source deep water and accordingly wider expansion of southernsource deep and bottom water masses during glacial times relative to interglacial times. Submarine
topography influenced the spatial and temporal patterns of deep water mass distribution.
Introdnction
Terrigenous matter makes up a considerable pro- debris from land to sea is mainly driven by the large
portion of total sediment accumulation in most river systems of Africa and South America, trade
Quaternary deposits of the South Atlantic and the winds from African deserts and glaciogenic supadjoining Southern Ocean. The primary source of ply from Antarctica, of which most material is
terrigenous matter is the physical and chemical trapped at the shelves (Milliman and Summerhayes
weathering and erosion of preexisting rocks and 1975; Windom 1975; Charnley 1989; Eisma 1993;
soils on the adjacent continents. At present, beside Grobe and Mackensen 1992; Ehrmann et a1. 1992).
some coastal erosion, significant input oflithogenic Transport of terrigenous particles to the deep-sea
From FISCHER G, WEFER G (eds), 1999, Use of Proxies in Paleoceanography: Examplesfrom the South Atlantic. Springer-Verlag
Berlin Heidelberg, pp 285-313
Deep Water Circulation in the South Atlantic
and the Adjoining Southern Ocean
B. Diekmann!', G. Kuhn!, A. Mackensenl,R. Petschick 2 , D.K. Filttererl,
R. Gersonde!, C. Riihlemann 3 and H.-S. Niebler 3
1 Alfred-Wegener-Institutfor Polar- und Meeresforschung, Postfach 12 0161,
D-27515 Bremerhaven, Germany
2 Geologisch-Palaeontologisches Institut, Universitiit Franlifurt,
Senckenberganlage 32-34,
D-60054 FranlifurtlMain, Germany
3Universitiit Bremen, Fachbereich Geowissenschaften, Postfach 330440,
D-28334 Bremen, Germany
*corresponding author (e-mail}:bdiekmann@awi-bremerhaven.de
Abstract: In the South Atlantic and adjoining Southern Ocean the kaolinite/chlorite-ratio in Late
Quaternary sediments are an alternative deep water proxy to benthic foraminiferal proxies and
carbonate preservation indices that is even suitable in regions with poor carbonate preservation.
This paper shows the relationship between modem abyssal circulation and the kaolinite/chloriteratio and presents reconstructions of deep and bottom water advection based on the kaolinite/
chlorite proxy. We also discuss the limitations and future perspectives of the kaolinite/chlorite proxy.
Latitudinal and water depth-related patterns of the kaolinite/chlorite-ratio in surface sediments
correspond to the modem deep and bottom water mass distribution. Kaolinite originates from lowlatitudes and traces North Atlantic Deep Water (northern-source deep water) advection to the
south. Chlorite from the southern high-latitudes is exported via northward advecting Antarctic
Bottom Water and Circumpolar Deep Water (southern-source deep and bottom water). Deep-sea
sedimentation in regions underlying the Antarctic Circumpolar Current was current-dominated
throughout the Late Quaternary. Temporal variations of the kaolinite/chlorite-ratio in response to
glacial-interglacial cycles reflect changing deep water mass configurations, suggesting a shallowing
and northward retreat of northern-source deep water and accordingly wider expansion of southernsource deep and bottom water masses during glacial times relative to interglacial times. Submarine
topography influenced the spatial and temporal patterns of deep water mass distribution.
Introdnction
Terrigenous matter makes up a considerable pro- debris from land to sea is mainly driven by the large
portion of total sediment accumulation in most river systems of Africa and South America, trade
Quaternary deposits of the South Atlantic and the winds from African deserts and glaciogenic supadjoining Southern Ocean. The primary source of ply from Antarctica, of which most material is
terrigenous matter is the physical and chemical trapped at the shelves (Milliman and Summerhayes
weathering and erosion of preexisting rocks and 1975; Windom 1975; Charnley 1989; Eisma 1993;
soils on the adjacent continents. At present, beside Grobe and Mackensen 1992; Ehrmann et a1. 1992).
some coastal erosion, significant input oflithogenic Transport of terrigenous particles to the deep-sea
From FISCHER G, WEFER G (eds), 1999, Use of Proxies in Paleoceanography: Examplesfrom the South Atlantic. Springer-Verlag
Berlin Heidelberg, pp 285-313