Stable Isotope Record and Late Quaternary Sedimentation Rates at the Antarctic Continental Margin

Grobe, Hannes; Mackensen, Andréas; Hubberten, Hans‐Wolfgang; Spieß, V.; Fütterer, Dieter K

doi:10.1007/978-94-009-2029-3_31

Cited by 24 publications

(15 citation statements)

References 39 publications

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“…This evidence is consistent with other recent studies, indicating low productivity in the Southern Ocean during glacial times (LABEYRIE and DUPLESSY, 1985;MACKENSEN et al, 1989;GROBE et al, 1990;MORTLOCK et al, 1991;GROBE and MACKENSEN, 1992). Estimates of sea ice distribution during the last glacial maximum show continuous ice coverage south of 60 °S (HAYS, 1978;COOKE and HAYS, 1982).…”

Section: Paleoceanographic Implicationssupporting

confidence: 91%

“…The stratigraphy of the cores discussed in this paper is based on the stable oxygen isotope record of two cores from Atka Bay, which was generated from benthic (Epistominella exigua) as well as planktonic foraminfera species (Neogloboquadrina pachyderma) (MACKENSEN et al, 1989;GROBE et al, 1990, GROBE andMACKENSEN, 1992). These are the only 18 O records of the Antarctic continental margin which could be correlated with the global isotope stratigraphy so far.…”

Section: Stratigraphymentioning

confidence: 99%

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Palaeoproductivity at the Antarctic continental margin: opal and barium records for the last 400 ka

Bonn¹,

Gingele²,

Grobe³

et al. 1998

Palaeogeography, Palaeoclimatology, Palaeoecology

136

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Records of biogenic opal and barium were measured in sediment cores at the Antarctic continental margin in the area of the Weddell, Lazarev and Cosmonaut seas. These records provide a qualitative and quantitative tool to estimate changes in paleoproductivity over the last 400 ka. The stratigraphy of the investigated cores is calibrated to a lithostratigraphy, adjusted to a stable isotope record from the eastern Weddell Sea, which is supported by a Th-dating method. We present evidence that interglacial productivity along the Antarctic continental margin is twice as high compared to subantarctic sites near South Orkney. A glacial/interglacial pattern with high productivity during peak warm stages can be observed back to 400 ka.High interglacial productivity is linked to a reduced sea ice coverage, which is regulated by the heat flux introduced by North Atlantic Deep Water (NADW) to the Antarctic Ocean. Generally, good correlations between the barium and opal records of the sediment cores indicate that dissolution of opal in the water column and the sediment does not obscure the surface productivity signal. Therefore, in this area biogenic opal in combination with other proxies, can be used for paleoproductivity estimates. Paleoproductivity is also assessed quantitatively from the barium record using the approaches of Dymond et al. (1992) and Francois et al. (1995).Paleoproductivity rates obtained by both methods show a good correspondence. In peak warm stages higher values are computed with the approach of Dymond et al. (1992). However, both methods provide values, which are representative of a highproductivity area. They are drastically reduced during glacial times. The extent and duration of sea ice coverage and the persistence of coastal polynyas is considered to be of primary importance in controlling the flux of biogenic material to sediments of the Antarctic continental margin.

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Section: Paleoceanographic Implicationssupporting

confidence: 91%

Section: Stratigraphymentioning

confidence: 99%

Palaeoproductivity at the Antarctic continental margin: opal and barium records for the last 400 ka

Bonn¹,

Gingele²,

Grobe³

et al. 1998

Palaeogeography, Palaeoclimatology, Palaeoecology

136

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show abstract

“…The large and continuous extent of sea ice is responsible for low primary productivity as the light supply in surface waters is reduced (Grobe et al, 1990).…”

Section: Discussionmentioning

confidence: 99%

“…Cyclic changes of sedimentary facies are well known in Pleistocene sediments from the Antarctic continental margin in the eastern Weddell Sea (Grobe, 1986;Grobe et al, 1990). The sediment composition in this area is also characterized by significant changes in the content of ice-rafted debris, grain-size distribution, clay mineral assemblage, and biogenic components.…”

Section: Introductionmentioning

confidence: 89%

Cyclic Sedimentation at Sites 745 and 746, Leg 119

Ehrmann¹,

Grobe²

1991

Proceedings of the Ocean Drilling Program

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The upper Miocene to Pleistocene sediments recovered at ODP Sites 745 and 746 in the Australian-Antarctic Basin are characterized by cyclic facies changes. Sedimentological investigations of a detailed Quaternary section reveal that facies A is dominated by a high content of siliceous microfossils, a relatively low terrigenous sediment content, an icerafted component, low concentrations of fine sediment particles, and a relatively high smectite content. This facies corresponds to interglacial sedimentary conditions. Facies B, in contrast, is characteristic of glacial conditions and is dominated by a large amount of terrigenous material and a smaller opaline component. There is also a prominent ice-rafted component. The microfossils commonly are reworked and broken. The clay mineral assemblages show higher proportions of glacially derived illite and chlorite.A combination of four different processes, attributed to glacial-interglacial cycles, was responsible for the cyclic facies changes during Quaternary time: transport by gravity, ice, and current and changes in primary productivity. Of great importance was the movement of the grounding line of the ice shelves, which directly influenced the intensity of ice rafting and of gravitational sediment transport to the deep sea. The extension of the ice shelves was also responsible for the generation of cold and erosive Antarctic Bottom Water, which controlled the grain-size distribution, particularly of the fine fraction, in the investigated area.

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“…However, it does not intend to discuss the climatic evolution of the southern high latitudes, which already has been reconstructed in great detail (e.g. Robert and Maillot, 1990;Grobe et al, 1990a;Ehrmann, 1991). For evaluating the significance of clay minerals, typical examples from different morphological and geological settings, such as the continental shelf, the continental slope, the adjacent deep-sea and isolated submarine elevations are investigated or reviewed.…”

Section: Introductionmentioning

confidence: 99%

Significance of clay mineral assemblages in the Antarctic Ocean

et al. 1992

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Ehrmann, W.U., Melles, M., Kuhn, G. and Grobe, H., 1992. Significance of clay mineral assemblages in the Antarctic Ocean.Mar. Geol., 107: 249-273. 249Typical examples from different morphological and geological settings in the Antarctic Ocean are reviewed in order to discuss the value of clay mineral assemblages for reconstructing the glacial history of Antarctica, the paleoceanographic history of the Antarctic Ocean and the sedimentary processes at the Antarctic continental margin. The significance of clay minerals for paleoenvironmental reconstructions strongly varies with both the position of the sites under investigation and the age of the sediments.In late Mesozoic to Paleogene sediments clay mineral assemblages are sensitive tools for reconstructing climatic conditions. For example, the shift from smectite-dominated assemblages to illite-and chlorite-dominated assemblages in the earliest Oligocene clearly documents the transition from chemical weathering conditions under a warm and humid climate to physical weathering under cooler conditions. Submarine elevations such as Maud Rise and Kerguelen Plateau give the best record for direct paleoclimatic and paleoceanographic studies. At the proximal sites of the continental slope and shelf, as well as in the deep sea, the paleoclimatic information normally is masked by a variety of processes resulting in sediment redistribution. At those sites, in contrast, the clay mineral assemblages bear a wealth of information on different sedimentary processes.After the establishment of a continental East Antarctic ice sheet, physical weathering prevailed. Variations in the clay mineral records predominantly reflect the influence of different sediment sources resulting from different glacial, hydrographic or gravitational transport processes. Because these sedimentation processes are generally linked to climatic variations, the clay mineral assemblages in most of the Neogene and Quaternary sediments provide indirect paleoclimatic information. The processes are best documented in the clay mineral composition in those areas where changes in source regions with distinct petrographic differences are expected and where distances from the source region are low.

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Stable Isotope Record and Late Quaternary Sedimentation Rates at the Antarctic Continental Margin

Cited by 24 publications

References 39 publications

Palaeoproductivity at the Antarctic continental margin: opal and barium records for the last 400 ka

Palaeoproductivity at the Antarctic continental margin: opal and barium records for the last 400 ka

Cyclic Sedimentation at Sites 745 and 746, Leg 119

Significance of clay mineral assemblages in the Antarctic Ocean

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