Sedimentological investigations and age constraints of sediment cores from the outer Abbot trough, Amundsen Sea shelf

DOI

Precise knowledge about the extent of the West Antarctic Ice Sheet (WAIS) at the Last Glacial Maximum (LGM; c. 26.5-19 cal. ka BP) is important in order to 1) improve paleo-ice sheet reconstructions, 2) provide a robust empirical framework for calibrating paleo-ice sheet models, and 3) locate potential shelf refugia for Antarctic benthos during the last glacial period. However, reliable reconstructions are still lacking for many WAIS sectors, particularly for key areas on the outer continental shelf, where the LGM-ice sheet is assumed to have terminated. In many areas of the outer continental shelf around Antarctica, direct geological data for the presence or absence of grounded ice during the LGM is lacking because of post-LGM iceberg scouring. This also applies to most of the outer continental shelf in the Amundsen Sea. Here we present detailed marine geophysical and new geological data documenting a sequence of glaciomarine sediments up to ~12 m thick within the deep outer portion of Abbot Trough, a palaeo-ice stream trough on the outer shelf of the Amundsen Sea Embayment. The upper 2-3 meters of this sediment drape contain calcareous foraminifera of Holocene and (pre-)LGM age and, in combination with palaeomagnetic age constraints, indicate that continuous glaciomarine deposition persisted here since well before the LGM, possibly even since the last interglacial period. Our data therefore indicate that the LGM grounding line, whose exact location was previously uncertain, did not reach the shelf edge everywhere in the Amundsen Sea. The LGM grounding line position coincides with the crest of a distinct grounding-zone wedge ~100 km inland from the continental shelf edge. Thus, an area of >6000 km² remained free of grounded ice through the last glacial cycle, requiring the LGM grounding line position to be re-located in this sector, and suggesting a new site at which Antarctic shelf benthos may have survived the last glacial period.

Supplement to: Klages, Johann Philipp; Kuhn, Gerhard; Hillenbrand, Claus-Dieter; Smith, James A; Graham, Alastair G C; Nitsche, Frank-Oliver; Frederichs, Thomas; Jernas, Patrycja E; Gohl, Karsten; Wacker, Lukas (2017): Limited grounding-line advance onto the West Antarctic continental shelf in the easternmost Amundsen Sea Embayment during the last glacial period. PLoS ONE, 12(7), e0181593

Identifier
DOI https://doi.org/10.1594/PANGAEA.857881
Related Identifier https://doi.org/10.1371/journal.pone.0181593
Metadata Access https://ws.pangaea.de/oai/provider?verb=GetRecord&metadataPrefix=datacite4&identifier=oai:pangaea.de:doi:10.1594/PANGAEA.857881
Provenance
Creator Klages, Johann Philipp ORCID logo; Kuhn, Gerhard ORCID logo; Hillenbrand, Claus-Dieter ORCID logo; Smith, James A ORCID logo; Graham, Alastair G C ORCID logo; Nitsche, Frank-Oliver (ORCID: 0000-0002-4137-547X); Frederichs, Thomas ORCID logo; Jernas, Patrycja E ORCID logo; Gohl, Karsten ORCID logo; Wacker, Lukas ORCID logo
Publisher PANGAEA
Publication Year 2017
Rights Creative Commons Attribution 3.0 Unported; https://creativecommons.org/licenses/by/3.0/
OpenAccess true
Representation
Language English
Resource Type Supplementary Publication Series of Datasets; Collection
Format application/zip
Size 17 datasets
Discipline Earth System Research
Spatial Coverage (-104.338W, -71.923S, -103.326E, -71.744N)
Temporal Coverage Begin 2006-02-26T16:12:00Z
Temporal Coverage End 2010-03-09T05:05:00Z