Geomorphology and till architecture of terrestrial palaeo-ice streams of the southwest Laurentide Ice Sheet : a borehole stratigraphic approach.
A multidimensional study, utilising geomorphological mapping and the analysis of regional borehole stratigraphy, is employed to elucidate the regional till architecture of terrestrial palaeo-ice streams relating to the Late Wisconsinan southwest Laurentide Ice Sheet. Detailed mapping over a 57,400 k...
Published in: | Quaternary Science Reviews |
---|---|
Main Authors: | , , |
Format: | Article in Journal/Newspaper |
Language: | unknown |
Published: |
Elsevier
2018
|
Subjects: | |
Online Access: | http://dro.dur.ac.uk/24173/ http://dro.dur.ac.uk/24173/1/24173.pdf https://doi.org/10.1016/j.quascirev.2017.12.018 |
id |
ftunivdurham:oai:dro.dur.ac.uk.OAI2:24173 |
---|---|
record_format |
openpolar |
spelling |
ftunivdurham:oai:dro.dur.ac.uk.OAI2:24173 2023-05-15T16:40:36+02:00 Geomorphology and till architecture of terrestrial palaeo-ice streams of the southwest Laurentide Ice Sheet : a borehole stratigraphic approach. Norris, S.L Evans, D.J.A. O Cofaigh, C. 2018-04-15 application/pdf http://dro.dur.ac.uk/24173/ http://dro.dur.ac.uk/24173/1/24173.pdf https://doi.org/10.1016/j.quascirev.2017.12.018 unknown Elsevier dro:24173 issn:0277-3791 doi:10.1016/j.quascirev.2017.12.018 http://dro.dur.ac.uk/24173/ https://doi.org/10.1016/j.quascirev.2017.12.018 http://dro.dur.ac.uk/24173/1/24173.pdf © 2018 This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/ CC-BY-NC-ND Quaternary science reviews, 2018, Vol.186, pp.186-214 [Peer Reviewed Journal] Article PeerReviewed 2018 ftunivdurham https://doi.org/10.1016/j.quascirev.2017.12.018 2020-06-04T22:24:29Z A multidimensional study, utilising geomorphological mapping and the analysis of regional borehole stratigraphy, is employed to elucidate the regional till architecture of terrestrial palaeo-ice streams relating to the Late Wisconsinan southwest Laurentide Ice Sheet. Detailed mapping over a 57,400 km2 area of southwestern Saskatchewan confirms previous reconstructions of a former southerly flowing ice stream, demarcated by a 800 km long corridor of megaflutes and mega-scale glacial lineations (Ice Stream 1) and cross cut by three, formerly southeast flowing ice streams (Ice Streams 2A, B and C). Analysis of the lithologic and geophysical characteristics of 197 borehole samples within these corridors reveals 17 stratigraphic units comprising multiple tills and associated stratified sediments overlying preglacial deposits, the till thicknesses varying with both topography and distance down corridor. Reconciling this regional till architecture with the surficial geomorphology reveals that surficial units are spatially consistent with a dynamic switch in flow direction, recorded by the cross cutting corridors of Ice Streams 1, 2A, B and C. The general thickening of tills towards lobate ice stream margins is consistent with subglacial deformation theory and variations in this pattern on a more localised scale are attributed to influences of subglacial topography including thickening at buried valley margins, thinning over uplands and thickening in overridden ice-marginal landforms. Article in Journal/Newspaper Ice Sheet Durham University: Durham Research Online Quaternary Science Reviews 186 186 214 |
institution |
Open Polar |
collection |
Durham University: Durham Research Online |
op_collection_id |
ftunivdurham |
language |
unknown |
description |
A multidimensional study, utilising geomorphological mapping and the analysis of regional borehole stratigraphy, is employed to elucidate the regional till architecture of terrestrial palaeo-ice streams relating to the Late Wisconsinan southwest Laurentide Ice Sheet. Detailed mapping over a 57,400 km2 area of southwestern Saskatchewan confirms previous reconstructions of a former southerly flowing ice stream, demarcated by a 800 km long corridor of megaflutes and mega-scale glacial lineations (Ice Stream 1) and cross cut by three, formerly southeast flowing ice streams (Ice Streams 2A, B and C). Analysis of the lithologic and geophysical characteristics of 197 borehole samples within these corridors reveals 17 stratigraphic units comprising multiple tills and associated stratified sediments overlying preglacial deposits, the till thicknesses varying with both topography and distance down corridor. Reconciling this regional till architecture with the surficial geomorphology reveals that surficial units are spatially consistent with a dynamic switch in flow direction, recorded by the cross cutting corridors of Ice Streams 1, 2A, B and C. The general thickening of tills towards lobate ice stream margins is consistent with subglacial deformation theory and variations in this pattern on a more localised scale are attributed to influences of subglacial topography including thickening at buried valley margins, thinning over uplands and thickening in overridden ice-marginal landforms. |
format |
Article in Journal/Newspaper |
author |
Norris, S.L Evans, D.J.A. O Cofaigh, C. |
spellingShingle |
Norris, S.L Evans, D.J.A. O Cofaigh, C. Geomorphology and till architecture of terrestrial palaeo-ice streams of the southwest Laurentide Ice Sheet : a borehole stratigraphic approach. |
author_facet |
Norris, S.L Evans, D.J.A. O Cofaigh, C. |
author_sort |
Norris, S.L |
title |
Geomorphology and till architecture of terrestrial palaeo-ice streams of the southwest Laurentide Ice Sheet : a borehole stratigraphic approach. |
title_short |
Geomorphology and till architecture of terrestrial palaeo-ice streams of the southwest Laurentide Ice Sheet : a borehole stratigraphic approach. |
title_full |
Geomorphology and till architecture of terrestrial palaeo-ice streams of the southwest Laurentide Ice Sheet : a borehole stratigraphic approach. |
title_fullStr |
Geomorphology and till architecture of terrestrial palaeo-ice streams of the southwest Laurentide Ice Sheet : a borehole stratigraphic approach. |
title_full_unstemmed |
Geomorphology and till architecture of terrestrial palaeo-ice streams of the southwest Laurentide Ice Sheet : a borehole stratigraphic approach. |
title_sort |
geomorphology and till architecture of terrestrial palaeo-ice streams of the southwest laurentide ice sheet : a borehole stratigraphic approach. |
publisher |
Elsevier |
publishDate |
2018 |
url |
http://dro.dur.ac.uk/24173/ http://dro.dur.ac.uk/24173/1/24173.pdf https://doi.org/10.1016/j.quascirev.2017.12.018 |
genre |
Ice Sheet |
genre_facet |
Ice Sheet |
op_source |
Quaternary science reviews, 2018, Vol.186, pp.186-214 [Peer Reviewed Journal] |
op_relation |
dro:24173 issn:0277-3791 doi:10.1016/j.quascirev.2017.12.018 http://dro.dur.ac.uk/24173/ https://doi.org/10.1016/j.quascirev.2017.12.018 http://dro.dur.ac.uk/24173/1/24173.pdf |
op_rights |
© 2018 This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/ |
op_rightsnorm |
CC-BY-NC-ND |
op_doi |
https://doi.org/10.1016/j.quascirev.2017.12.018 |
container_title |
Quaternary Science Reviews |
container_volume |
186 |
container_start_page |
186 |
op_container_end_page |
214 |
_version_ |
1766031003060535296 |