Coeval brittle and ductile deformation beneath the late Wisconsinan Puget Lobe, Washington State, USA

Abstract Late Wisconsinan glacial sediments, exposed on Whidbey Island and Camano Island, Puget Sound (Washington State, USA), were deposited in a proglacial shallow marine/outwash environment during northward retreat of the Puget Lobe of the Cordilleran ice sheet. Sediments mainly comprise massive...

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Published in:Annals of Glaciology
Main Author: Knight, Jasper
Format: Article in Journal/Newspaper
Language:English
Published: Cambridge University Press (CUP) 2019
Subjects:
Annals of Glaciology
Ice Sheet
Online Access:http://dx.doi.org/10.1017/aog.2019.33
https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0260305519000338
id crcambridgeupr:10.1017/aog.2019.33
record_format openpolar
spelling crcambridgeupr:10.1017/aog.2019.33 2024-06-09T07:38:27+00:00 Coeval brittle and ductile deformation beneath the late Wisconsinan Puget Lobe, Washington State, USA Knight, Jasper 2019 http://dx.doi.org/10.1017/aog.2019.33 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0260305519000338 en eng Cambridge University Press (CUP) http://creativecommons.org/licenses/by/4.0/ Annals of Glaciology volume 60, issue 80, page 100-114 ISSN 0260-3055 1727-5644 journal-article 2019 crcambridgeupr https://doi.org/10.1017/aog.2019.33 2024-05-15T13:04:30Z Abstract Late Wisconsinan glacial sediments, exposed on Whidbey Island and Camano Island, Puget Sound (Washington State, USA), were deposited in a proglacial shallow marine/outwash environment during northward retreat of the Puget Lobe of the Cordilleran ice sheet. Sediments mainly comprise massive and cross-bedded sand and gravels, and rhythmically-bedded clay and silt/fine sand couplets, interbedded with diamictons that were deposited by a range of mass flows of different viscosities. Although sediment stratigraphy and ice advance–retreat patterns are well established for the Puget Lobe, brittle and ductile deformation structures within, and separating, these sediment units are less well understood. These structures record the nature of ice–bed interactions taking place in subglacial and proglacial environments. This study examines evidence for these processes and environments. Key deformation structures identified include open to overturned folds, normal and reverse faults, clastic dikes and hydrofractures and passive-loading structures. Evidence for coeval development of ductile and brittle deformation structures shows the close relationship between porewater changes, sediment rheology and sediment system responses to changes in strain caused by ice–bed interactions. Article in Journal/Newspaper Annals of Glaciology Ice Sheet Cambridge University Press Annals of Glaciology 60 80 100 114
institution Open Polar
collection Cambridge University Press
op_collection_id crcambridgeupr
language English
description Abstract Late Wisconsinan glacial sediments, exposed on Whidbey Island and Camano Island, Puget Sound (Washington State, USA), were deposited in a proglacial shallow marine/outwash environment during northward retreat of the Puget Lobe of the Cordilleran ice sheet. Sediments mainly comprise massive and cross-bedded sand and gravels, and rhythmically-bedded clay and silt/fine sand couplets, interbedded with diamictons that were deposited by a range of mass flows of different viscosities. Although sediment stratigraphy and ice advance–retreat patterns are well established for the Puget Lobe, brittle and ductile deformation structures within, and separating, these sediment units are less well understood. These structures record the nature of ice–bed interactions taking place in subglacial and proglacial environments. This study examines evidence for these processes and environments. Key deformation structures identified include open to overturned folds, normal and reverse faults, clastic dikes and hydrofractures and passive-loading structures. Evidence for coeval development of ductile and brittle deformation structures shows the close relationship between porewater changes, sediment rheology and sediment system responses to changes in strain caused by ice–bed interactions.
format Article in Journal/Newspaper
author Knight, Jasper
spellingShingle Knight, Jasper
Coeval brittle and ductile deformation beneath the late Wisconsinan Puget Lobe, Washington State, USA
author_facet Knight, Jasper
author_sort Knight, Jasper
title Coeval brittle and ductile deformation beneath the late Wisconsinan Puget Lobe, Washington State, USA
title_short Coeval brittle and ductile deformation beneath the late Wisconsinan Puget Lobe, Washington State, USA
title_full Coeval brittle and ductile deformation beneath the late Wisconsinan Puget Lobe, Washington State, USA
title_fullStr Coeval brittle and ductile deformation beneath the late Wisconsinan Puget Lobe, Washington State, USA
title_full_unstemmed Coeval brittle and ductile deformation beneath the late Wisconsinan Puget Lobe, Washington State, USA
title_sort coeval brittle and ductile deformation beneath the late wisconsinan puget lobe, washington state, usa
publisher Cambridge University Press (CUP)
publishDate 2019
url http://dx.doi.org/10.1017/aog.2019.33
https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0260305519000338
genre Annals of Glaciology
Ice Sheet
genre_facet Annals of Glaciology
Ice Sheet
op_source Annals of Glaciology
volume 60, issue 80, page 100-114
ISSN 0260-3055 1727-5644
op_rights http://creativecommons.org/licenses/by/4.0/
op_doi https://doi.org/10.1017/aog.2019.33
container_title Annals of Glaciology
container_volume 60
container_issue 80
container_start_page 100
op_container_end_page 114
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