Grain size composition of sediment cores from the Weddell Sea, Antarctica

Sedimentary processes in the southeastern Weddell Sea are influenced by glacial-interglacial ice-shelf dynamics and the cyclonic circulation of the Weddell Gyre, which affects all water masses down to the sea floor. Significantly increased sedimentation rates occur during glacial stages, when ice sheets advance to the shelf edge and trigger gravitational sediment transport to the deep sea. Downslope transport on the Crary Fan and off Dronning Maud and Coats Land is channelized into three huge channel systems, which originate on the eastern-, the central and the western Crary Fan. They gradually turn from a northerly direction eastward until they follow a course parallel to the continental slope. All channels show strongly asymmetric cross sections with well-developed levees on their northwestern sides, forming wedge-shaped sediment bodies. They level off very gently. Levees on the southeastern sides are small, if present at all. This characteristic morphology likely results from the process of combined turbidite-contourite deposition. Strong thermohaline currents of the Weddell Gyre entrain particles from turbidity-current suspensions, which flow down the channels, and carry them westward out of the channel where they settle on a surface gently dipping away from the channel. These sediments are intercalated with overbank deposits of high-energy and high-volume turbidity currents, which preferentially flood the left of the channels (looking downchannel) as a result of Coriolis force. In the distal setting of the easternmost channel-levee complex, where thermohaline currents are directed northeastward as a result of a recirculation of water masses from the Enderby Basin, the setting and the internal structures of a wedge-shaped sediment body indicate a contourite drift rather than a channel levee. Dating of the sediments reveals that the levees in their present form started to develop with a late Miocene cooling event, which caused an expansion of the East Antarctic Ice Sheet and an invigoration of thermohaline current activity.

Supplement to: Michels, Klaus; Kuhn, Gerhard; Hillenbrand, Claus-Dieter; Diekmann, Bernhard; Fütterer, Dieter K; Grobe, Hannes; Uenzelmann-Neben, Gabriele (2002): The southern Weddell Sea: combined contourite-turbidite sedimentation at the southeastern margin of the Weddell Gyre. In: Stow, D A V; Pudsey, C; Howe, J C; Faugères, J-C & Viana, A R (eds.), Deep-water contourite systems: modern drifts and ancient series, seismic and sedimentary characteristics. Geological Society of London, Memoirs, London, 22, 305-323

Metadata Access
Creator Michels, Klaus; Kuhn, Gerhard (ORCID: 0000-0001-6069-7485); Hillenbrand, Claus-Dieter (ORCID: 0000-0003-0240-7317); Diekmann, Bernhard (ORCID: 0000-0001-5129-3649); Fütterer, Dieter K; Grobe, Hannes (ORCID: 0000-0002-4133-2218); Uenzelmann-Neben, Gabriele (ORCID: 0000-0002-0115-5923)
Publisher PANGAEA
Publication Year 2002
Rights Creative Commons Attribution 3.0 Unported;
OpenAccess true
Language English
Resource Type Supplementary Publication Series of Datasets; Collection
Format application/zip
Size 13 datasets
Discipline Earth System Research
Spatial Coverage (-33.649W, -74.241S, -16.500E, -71.869N); Camp Norway; Halley Bay; Weddell Sea; Lyddan Island
Temporal Coverage Begin 1985-12-18T23:15:00Z
Temporal Coverage End 1990-01-15T00:04:00Z