Sedimentology of the southern Bellingshausen Sea

DOI

A major trough ('Belgica Trough') eroded by a palaeo-ice stream crosses the continental shelf of the southern Bellingshausen Sea (West Antarctica) and is associated with a trough mouth fan ('Belgica TMF') on the adjacent continental slope. Previous marine geophysical and geological studies investigated the bathymetry and geomorphology of Belgica Trough and Belgica TMF, erosional and depositional processes associated with bedform formation, and the temporal and spatial changes in clay mineral provenance of subglacial and glaciomarine sediments. Here, we present multi-proxy data from sediment cores recovered from the shelf and uppermost slope in the southern Bellingshausen Sea and reconstruct the ice-sheet history since the last glacial maximum (LGM) in this poorly studied area of West Antarctica. We combined new data (physical properties, sedimentary structures, geochemical and grain-size data) with published data (shear strength, clay mineral assemblages) to refine a previous facies classification for the sediments. The multi-proxy approach allowed us to distinguish four main facies types and to assign them to the following depositional settings: 1) subglacial, 2) proximal grounding-line, 3) distal sub-ice shelf/subsea ice, and 4) seasonal open-marine. In the seasonal open-marine facies we found evidence for episodic current-induced winnowing of near-seabed sediments on the middle to outer shelf and at the uppermost slope during the late Holocene.In addition, we obtained data on excess 210Pb activity at three core sites and 44 AMS 14C dates from the acid-insoluble fraction of organic matter (AIO) and calcareous (micro-)fossils, respectively, at 12 sites. These chronological data enabled us to reconstruct, for the first time, the timing of the last advance and retreat of the West Antarctic Ice Sheet (WAIS) and the Antarctic Peninsula Ice Sheet (APIS) in the southern Bellingshausen Sea. We used the down-core variability in sediment provenance inferred from clay mineral changes to identify the most reliable AIO 14C ages for ice-sheet retreat. The palaeo-ice stream advanced through Belgica Trough after ~36.0 corrected 14C ka before present (B.P.). It retreated from the outer shelf at ~25.5 ka B.P., the middle shelf at ~19.8 ka B.P., the inner shelf in Eltanin Bay at ~12.3 ka B.P., and the inner shelf in Ronne Entrance at ~6.3 ka B.P.. The retreat of the WAIS and APIS occurred slowly and stepwise, and may still be in progress. This dynamical ice-sheet behaviour has to be taken into account for the interpretation of recent and the prediction of future mass-balance changes in the study area. The glacial history of the southern Bellingshausen Sea is unique when compared to other regions in West Antarctica, but some open questions regarding its chronology need to be addressed by future work.

Supplement to: Hillenbrand, Claus-Dieter; Larter, Robert D; Dowdeswell, Julian A; Ehrmann, Werner; Ó Cofaigh, Colm; Benetti, Sara; Graham, Alastair G C; Grobe, Hannes (2010): The sedimentary legacy of a palaeo-ice stream on the shelf of the southern Bellingshausen Sea: Clues to West Antarctic glacial history during the Late Quaternary. Quaternary Science Reviews, 29(19-20), 2741-2763

Identifier
DOI https://doi.org/10.1594/PANGAEA.742532
Related Identifier https://doi.org/10.1016/j.quascirev.2010.06.028
Metadata Access https://ws.pangaea.de/oai/provider?verb=GetRecord&metadataPrefix=datacite4&identifier=oai:pangaea.de:doi:10.1594/PANGAEA.742532
Provenance
Creator Hillenbrand, Claus-Dieter ORCID logo; Larter, Robert D ORCID logo; Dowdeswell, Julian A ORCID logo; Ehrmann, Werner; Ó Cofaigh, Colm; Benetti, Sara ORCID logo; Graham, Alastair G C ORCID logo; Grobe, Hannes ORCID logo
Publisher PANGAEA
Publication Year 2010
Funding Reference German Research Foundation https://doi.org/10.13039/501100001659 Crossref Funder ID 5472008 https://gepris.dfg.de/gepris/projekt/5472008 Priority Programme 1158 Antarctic Research with Comparable Investigations in Arctic Sea Ice Areas
Rights Creative Commons Attribution 3.0 Unported; https://creativecommons.org/licenses/by/3.0/
OpenAccess true
Representation
Resource Type Supplementary Publication Series of Datasets; Collection
Format application/zip
Size 20 datasets
Discipline Earth System Research
Spatial Coverage (-89.357W, -73.402S, -72.575E, -70.005N); Bellingshausen Sea, inbetween gullies at uppermost slope on TMF; Bellingshausen Sea, till sheet on shelf N of Smyley Island; Bellingshausen Sea, till sheet on N side of Ronne Entrance Trough; Bellingshausen Sea; Bellingshausen Sea, part of trough exiting Carroll Inlet; MSGL/drumlins trend 335¡; Bellingshausen Sea, deep part of trough in Eltanin Bay; Bellingshausen Sea, central axis of trough, middle shelf; Bellingshausen Sea, toe of eastern bank of mini trough, outer shelf; Bellingshausen Sea, small escarpment at shelf break; Bellingshausen Sea, ridge-groove province: flattish groove; Bellingshausen Sea, ridge-groove province: ridge; Bellingshausen Sea, shallow part of trough in Eltanin Bay; Bellingshausen Sea, western flank of trough, middle shelf; Bellingshausen Sea, central axis of trough, outer shelf; Bellingshausen Sea, eastern bank of mini trough, outer shelf
Temporal Coverage Begin 1994-02-05T01:11:00Z
Temporal Coverage End 2004-02-05T00:00:00Z