Grünig, Sigrun (1991): Sedimentology on cores off the South Orkney Plateau. PANGAEA, https://doi.org/10.1594/PANGAEA.860528, Supplement to: Grünig, S (1991): Quartäre Sedimentationsprozesse am Kontinentalhang des Süd-Orkney-Plateaus im nordwestlichen Weddellmeer (Antarktis) (Quaternary sedimentation processes on the continental margin of the South Orkney Plateau, NW Weddell Sea (Antarctica). Berichte zur Polarforschung = Reports on Polar Research, 75, 196 pp, https://doi.org/10.2312/BzP_0075_1991
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Grab samples and cores for sedimentological studies were retrieved along a N-S transect of the South Orkney Plateau margin. On the basis of morphology, the margin has been subdivided into shelf, upper continental slope, and a lower slope region cut by basins and ridges.
Grain size, Sand component, and clay mineralogy were determined as well as water, organic carbon and carbonate contents. In addition, vane shear strength, magnetic intensity and the proportion of ice-rafted debris were measured, dating was done by detailed magnetic stratigraphy, the biofluctuation of the radiolarian Cycladophora davisiana and 230-Thorium analyses.
Sediment facies distribution is controlled by numerous factors such as regional bathymetry and circulation, biogenic productivity, seasonal ice cover and the deposition of terrigenous detritus by ice-rafting, bottom water transport and/or slumping. The complex interrelationship between these factors results in three main categories of sediment facies. The diamict facies is interpreted as an interglacial facies.
It is composed of clayey silt and silt and is characterised by a large component of coarse, ice-rafted material such as gravel and sand (IRD). This generally strongly bioturbated sediment contains radiolarian and diatom-rich layers as well as horizons of lower water and organic carbon content. Magnetic intensities, related to volcanic ash particles, glauconite, and micromanganese nodules as well as a large quantity of rock fragments, are low. The biosiliceous and IRD content decreases from north to south along the South Orkney transect because of seasonal ice margin fluctuations, thus resulting in barren and IRD-poor interglacial deposits in the southern region. Apart from ice-rafting and biogenic productivity, bottom currents also exert a strong control on the distribution of this facies. Strong and fluctuating bottom current influence is documented by the sediment structures in this facies.
The homogenous clay facies was deposited during glacial periods. These silty clays are generally barren with little ice-rafted material or rock fragments because of ice cover during glacial periods. The homogenous clay facies was probably deposited by bottom currents (contourite). In comparison to interglacial periods, current velocities during glacial periods must have been relatively weak due to the decreased formation of Antarctic Bottom Water and reduced water mass circulation.
The homogenous clays are additionally characterised by higher water and organic carbon contents as well as higher magnetic intensity. They are only weakly bioturbated with burrows size smaller than in the diamictite facies.
A bioturbated clay-size facies, with a composition similar to that of the diamictite facies, was deposited during the glacial to interglacial transition. The difference lies in the lower IRD and microfossil content. A weak current regime is indicated by the texture and sediment structures.
On the basis of sediment sequences, three glacial and four interglacial periods have been distinguished in cores PS1175-3, PS1170, and PS1167-9. The time span ranges from the Holocene to the interglacial at 340,000-300,000 Y.
Increased IRD deposition by icebergs and an increase in the production of siliceous organisms occured during the maximum of the last glacial due to several short surges of the Antarctic ice shelf.
Brehme, Isa (1992): Sedimentfazies und Bodenwasserstrom am Kontinentalhang des nordwestlichen Weddellmeeres (Sediment facies and bottomwater current on the continental slope in the northwestern Weddell Sea). Berichte zur Polarforschung = Reports on Polar Research, 110, 127 pp, https://doi.org/10.2312/BzP_0110_1992
Fütterer, Dieter K (1984): Die Expedition ANTARKTIS-II mit FS POLARSTERN 1983/84. Berichte zur Polarforschung = Reports on Polar Research, 18, 92 pp, https://doi.org/10.2312/BzP_0018_1984
Median Latitude: -63.569845 * Median Longitude: -44.463850 * South-bound Latitude: -63.959160 * West-bound Longitude: -44.608299 * North-bound Latitude: -63.458301 * East-bound Longitude: -44.047000
Date/Time Start: 1983-12-12T00:00:00 * Date/Time End: 1983-12-13T00:00:00
PS1167-10 (PS04/254) * Latitude: -63.959160 * Longitude: -44.047000 * Date/Time: 1983-12-12T01:55:00 * Elevation: -4459.0 m * Penetration: 11.5 m * Recovery: 10.06 m * Location: Weddell Sea * Campaign: ANT-II/3 (PS04) * Basis: Polarstern * Method/Device: Piston corer Meischner small (KL_Mk)
PS1169-1 (PS04/256) * Latitude: -63.458301 * Longitude: -44.608299 * Date/Time: 1983-12-12T00:00:00 * Elevation: -3844.0 m * Penetration: 0.32 m * Recovery: 0.55 m * Location: South Orkney * Campaign: ANT-II/3 (PS04) * Basis: Polarstern * Method/Device: Giant box corer (GKG)
PS1170-1 (PS04/257) * Latitude: -63.518290 * Longitude: -44.520000 * Date/Time: 1983-12-12T00:00:00 * Elevation: -3803.0 m * Penetration: 10 m * Recovery: 6.58 m * Location: Weddell Sea * Campaign: ANT-II/3 (PS04) * Basis: Polarstern * Method/Device: Gravity corer (Kiel type) (SL) * Comment: 9 core sections: 0-0.99, 0.99-1, 1-1.99, 1.99-2.99, 2.99-3.01, 3.01-4.01, 4.01-4.72, 4.72-5.72, 5.72-6.72 m
Datasets listed in this publication series
- Grobe, H; Fütterer, DK (1991): Documentation of sediment core PS1167-10. https://doi.org/10.1594/PANGAEA.204164
- Grobe, H; Fütterer, DK (1991): Documentation of sediment core PS1169-1. https://doi.org/10.1594/PANGAEA.107646
- Grobe, H; Fütterer, DK (1991): Documentation of sediment core PS1170-1. https://doi.org/10.1594/PANGAEA.271558
- Grobe, H; Fütterer, DK (1991): Documentation of sediment core PS1170-4. https://doi.org/10.1594/PANGAEA.107648
- Grünig, S (1999): Coarse fraction analysis of sediment core PS1170-1. https://doi.org/10.1594/PANGAEA.54432
- Grünig, S (1999): Granulometry of sediment core PS1170-1. https://doi.pangaea.de/10.1594/PANGAEA.54433
- Grünig, S (1999): Paleomagnetic analysis of sediment core PS1170-1. https://doi.org/10.1594/PANGAEA.54434
- Grünig, S (1999): Paleomagnetic of sediment core PS1167-10. https://doi.org/10.1594/PANGAEA.54447
- Grünig, S (1999): Sand fraction analysis of sediment core PS1170-1. https://doi.org/10.1594/PANGAEA.54435
- Grünig, S (1999): Sedimentology of core PS1170-1. https://doi.org/10.1594/PANGAEA.54436
- Grünig, S (1996): Sedimentology of core PS1170-4. https://doi.org/10.1594/PANGAEA.51550
- Grünig, S (1996): Water content and total organic carbon of sediment core PS1169-1. https://doi.org/10.1594/PANGAEA.51548
- Grünig, S (1996): Water content and total organic carbon of sediment core PS1171-1. https://doi.org/10.1594/PANGAEA.51551
- Grünig, S (1999): Water content of sediment core PS1170-1. https://doi.org/10.1594/PANGAEA.54437