Contrasting sources for glacial and interglacial shelf sediments used to interpret changing ice flow directions in the Larsen Basin, northern Antarctic Peninsula
Marine sediment cores from the former Larsen A Ice Shelf area reveal three lithological units deposited during ice sheet advance and retreat from the continental shelf. The uppermost Unit 1 consists of a diatom-bearing silty clay with sparse ice-rafted debris (IRD). Clasts include rock types which c...
Published in: | Marine Geology |
---|---|
Main Authors: | , , , , |
Format: | Article in Journal/Newspaper |
Language: | unknown |
Published: |
Elsevier
2009
|
Subjects: | |
Online Access: | http://nora.nerc.ac.uk/id/eprint/11189/ http://www.sciencedirect.com/science?_ob=MImg&_imagekey=B6V6M-4X0XFGT-3-T&_cdi=5818&_user=1773399&_orig=browse&_coverDate=10%2F15%2F2009&_sk=997339998&view=c&wchp=dGLbVlW-zSkzV&md5=699fb8b003243e725332a3a0c805b662&ie=/sdarticle.pdf |
id |
ftnerc:oai:nora.nerc.ac.uk:11189 |
---|---|
record_format |
openpolar |
spelling |
ftnerc:oai:nora.nerc.ac.uk:11189 2023-05-15T13:45:10+02:00 Contrasting sources for glacial and interglacial shelf sediments used to interpret changing ice flow directions in the Larsen Basin, northern Antarctic Peninsula Reinardy, Benedict T.I. Pudsey, Carol J. Hillenbrand, Claus-Dieter Murray, Tavi Evans, Jeffrey 2009 http://nora.nerc.ac.uk/id/eprint/11189/ http://www.sciencedirect.com/science?_ob=MImg&_imagekey=B6V6M-4X0XFGT-3-T&_cdi=5818&_user=1773399&_orig=browse&_coverDate=10%2F15%2F2009&_sk=997339998&view=c&wchp=dGLbVlW-zSkzV&md5=699fb8b003243e725332a3a0c805b662&ie=/sdarticle.pdf unknown Elsevier Reinardy, Benedict T.I.; Pudsey, Carol J.; Hillenbrand, Claus-Dieter orcid:0000-0003-0240-7317 Murray, Tavi; Evans, Jeffrey. 2009 Contrasting sources for glacial and interglacial shelf sediments used to interpret changing ice flow directions in the Larsen Basin, northern Antarctic Peninsula. Marine Geology, 266 (1-4). 156-171. https://doi.org/10.1016/j.margeo.2009.08.003 <https://doi.org/10.1016/j.margeo.2009.08.003> Marine Sciences Glaciology Earth Sciences Publication - Article PeerReviewed 2009 ftnerc https://doi.org/10.1016/j.margeo.2009.08.003 2023-02-04T19:27:12Z Marine sediment cores from the former Larsen A Ice Shelf area reveal three lithological units deposited during ice sheet advance and retreat from the continental shelf. The uppermost Unit 1 consists of a diatom-bearing silty clay with sparse ice-rafted debris (IRD). Clasts include rock types which can all be matched to onshore outcrops along the eastern side of the Antarctic Peninsula. Most clasts are very angular, angular or subangular. The clasts in this unit are interpreted as supraglacial or englacial debris deposited below an ice shelf distal from the grounding line and/or by icebergs in an open marine setting during the Holocene. In the underlying Units 2 and 3 clast lithologies are quite different and mainly comprise Cretaceous and Jurassic sedimentary rocks. These lithologies were derived locally from the continental shelf (the Larsen Basin) rather than the limited onshore outcrops. Of the 2750 clasts studied in Units 2 and 3, most are subrounded or subangular, and some are striated. Unit 2 is interpreted as being deposited beneath an ice shelf proximal to the grounding line. Unit 3 is interpreted as subglacial diamict deposited by grounded ice flowing across the shelf during the last glacial period. The availability of sedimentary rocks at the seabed may have facilitated the development of a deforming till layer with low shear strength (i.e. soft or deformation till) within Unit 3. There are no consistent differences in clast composition or roundness between the deformation till, which was probably deposited at the base of an ice stream, and an underlying till with high shear strength (i.e. stiff till). On the inner shelf where the bedrock lies very close to the seabed, clast composition in the subglacial diamicts affords a way of identifying the presence of Mesozoic stratigraphic units. The contrasting provenance of the coarse fraction between Unit 1 and Units 2 and 3 is used to interpret ice sheet basal thermal regime and produce a conceptual model of changing palaeo-flow directions between glacial ... Article in Journal/Newspaper Antarc* Antarctic Antarctic Peninsula Ice Sheet Ice Shelf Iceberg* Natural Environment Research Council: NERC Open Research Archive Antarctic Antarctic Peninsula Larsen Basin ENVELOPE(-60.000,-60.000,-68.000,-68.000) The Antarctic Marine Geology 266 1-4 156 171 |
institution |
Open Polar |
collection |
Natural Environment Research Council: NERC Open Research Archive |
op_collection_id |
ftnerc |
language |
unknown |
topic |
Marine Sciences Glaciology Earth Sciences |
spellingShingle |
Marine Sciences Glaciology Earth Sciences Reinardy, Benedict T.I. Pudsey, Carol J. Hillenbrand, Claus-Dieter Murray, Tavi Evans, Jeffrey Contrasting sources for glacial and interglacial shelf sediments used to interpret changing ice flow directions in the Larsen Basin, northern Antarctic Peninsula |
topic_facet |
Marine Sciences Glaciology Earth Sciences |
description |
Marine sediment cores from the former Larsen A Ice Shelf area reveal three lithological units deposited during ice sheet advance and retreat from the continental shelf. The uppermost Unit 1 consists of a diatom-bearing silty clay with sparse ice-rafted debris (IRD). Clasts include rock types which can all be matched to onshore outcrops along the eastern side of the Antarctic Peninsula. Most clasts are very angular, angular or subangular. The clasts in this unit are interpreted as supraglacial or englacial debris deposited below an ice shelf distal from the grounding line and/or by icebergs in an open marine setting during the Holocene. In the underlying Units 2 and 3 clast lithologies are quite different and mainly comprise Cretaceous and Jurassic sedimentary rocks. These lithologies were derived locally from the continental shelf (the Larsen Basin) rather than the limited onshore outcrops. Of the 2750 clasts studied in Units 2 and 3, most are subrounded or subangular, and some are striated. Unit 2 is interpreted as being deposited beneath an ice shelf proximal to the grounding line. Unit 3 is interpreted as subglacial diamict deposited by grounded ice flowing across the shelf during the last glacial period. The availability of sedimentary rocks at the seabed may have facilitated the development of a deforming till layer with low shear strength (i.e. soft or deformation till) within Unit 3. There are no consistent differences in clast composition or roundness between the deformation till, which was probably deposited at the base of an ice stream, and an underlying till with high shear strength (i.e. stiff till). On the inner shelf where the bedrock lies very close to the seabed, clast composition in the subglacial diamicts affords a way of identifying the presence of Mesozoic stratigraphic units. The contrasting provenance of the coarse fraction between Unit 1 and Units 2 and 3 is used to interpret ice sheet basal thermal regime and produce a conceptual model of changing palaeo-flow directions between glacial ... |
format |
Article in Journal/Newspaper |
author |
Reinardy, Benedict T.I. Pudsey, Carol J. Hillenbrand, Claus-Dieter Murray, Tavi Evans, Jeffrey |
author_facet |
Reinardy, Benedict T.I. Pudsey, Carol J. Hillenbrand, Claus-Dieter Murray, Tavi Evans, Jeffrey |
author_sort |
Reinardy, Benedict T.I. |
title |
Contrasting sources for glacial and interglacial shelf sediments used to interpret changing ice flow directions in the Larsen Basin, northern Antarctic Peninsula |
title_short |
Contrasting sources for glacial and interglacial shelf sediments used to interpret changing ice flow directions in the Larsen Basin, northern Antarctic Peninsula |
title_full |
Contrasting sources for glacial and interglacial shelf sediments used to interpret changing ice flow directions in the Larsen Basin, northern Antarctic Peninsula |
title_fullStr |
Contrasting sources for glacial and interglacial shelf sediments used to interpret changing ice flow directions in the Larsen Basin, northern Antarctic Peninsula |
title_full_unstemmed |
Contrasting sources for glacial and interglacial shelf sediments used to interpret changing ice flow directions in the Larsen Basin, northern Antarctic Peninsula |
title_sort |
contrasting sources for glacial and interglacial shelf sediments used to interpret changing ice flow directions in the larsen basin, northern antarctic peninsula |
publisher |
Elsevier |
publishDate |
2009 |
url |
http://nora.nerc.ac.uk/id/eprint/11189/ http://www.sciencedirect.com/science?_ob=MImg&_imagekey=B6V6M-4X0XFGT-3-T&_cdi=5818&_user=1773399&_orig=browse&_coverDate=10%2F15%2F2009&_sk=997339998&view=c&wchp=dGLbVlW-zSkzV&md5=699fb8b003243e725332a3a0c805b662&ie=/sdarticle.pdf |
long_lat |
ENVELOPE(-60.000,-60.000,-68.000,-68.000) |
geographic |
Antarctic Antarctic Peninsula Larsen Basin The Antarctic |
geographic_facet |
Antarctic Antarctic Peninsula Larsen Basin The Antarctic |
genre |
Antarc* Antarctic Antarctic Peninsula Ice Sheet Ice Shelf Iceberg* |
genre_facet |
Antarc* Antarctic Antarctic Peninsula Ice Sheet Ice Shelf Iceberg* |
op_relation |
Reinardy, Benedict T.I.; Pudsey, Carol J.; Hillenbrand, Claus-Dieter orcid:0000-0003-0240-7317 Murray, Tavi; Evans, Jeffrey. 2009 Contrasting sources for glacial and interglacial shelf sediments used to interpret changing ice flow directions in the Larsen Basin, northern Antarctic Peninsula. Marine Geology, 266 (1-4). 156-171. https://doi.org/10.1016/j.margeo.2009.08.003 <https://doi.org/10.1016/j.margeo.2009.08.003> |
op_doi |
https://doi.org/10.1016/j.margeo.2009.08.003 |
container_title |
Marine Geology |
container_volume |
266 |
container_issue |
1-4 |
container_start_page |
156 |
op_container_end_page |
171 |
_version_ |
1766214428602138624 |