Bar deposition in glacial outburst floods: scaling, post-flood reworking, and implications for the geomorphological and sedimentary record
The appearance of a flood deposit in the geomorphological and sedimentary record is a product of the both the processes operating during the flood, and those that occur afterwards and overprinting the deposit with a record of ‘normal’ processes. Nearly half of the total discharge of the November 199...
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Online Access: | http://hdl.handle.net/10034/605920 https://doi.org/10.4000/geomorphologie.11262 |
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ftchesteruniv:oai:chesterrep.openrepository.com:10034/605920 2023-05-15T16:21:48+02:00 Bar deposition in glacial outburst floods: scaling, post-flood reworking, and implications for the geomorphological and sedimentary record Marren, Philip M. University of Chester 2016-04-19 http://hdl.handle.net/10034/605920 https://doi.org/10.4000/geomorphologie.11262 en eng GFG http://geomorphologie.revues.org/11262 Marren, P. M. (2016). Bar deposition in glacial outburst floods: scaling, post-flood reworking, and implications for the geomorphological and sedimentary record. Géomorphologie: relief, processus, environnement, 22(1), 51-60. DOI:10.4000/geomorphologie.11262 doi:10.4000/geomorphologie.11262 http://hdl.handle.net/10034/605920 1957-777X Géomorphologie : relief, processus, environnement http://creativecommons.org/licenses/by-nc-nd/4.0/ CC-BY-NC-ND Fluvial geomorphology Iceland Braided river Jokulhlaup Proglacial Article 2016 ftchesteruniv https://doi.org/10.4000/geomorphologie.11262 2022-03-02T19:57:21Z The appearance of a flood deposit in the geomorphological and sedimentary record is a product of the both the processes operating during the flood, and those that occur afterwards and overprinting the deposit with a record of ‘normal’ processes. Nearly half of the total discharge of the November 1996 jökulhlaup on Skeiðarársandur was discharged through the Skeiðará river. The flood deposits have been extensively reworked since, up until 2009 when the channel was abandoned, effectively leaving the Skeiðará as a terrace, when retreat of Skeiðarárjökull directed meltwater to the adjacent Gígjukvísl river system. This paper describes the creation and modification of jökulhlaup barforms in the Skeiðará river, relating the changes to post-flood fluvial processes and glacier retreat. Large compound bars formed from the amalgamation of unit bars up to 1.5 km long. The location of the compound bars was governed by the macro-scale topography of the flood channel, and their size by upstream channel width in accordance with bar-scaling theory. Jökulhlaup bars are therefore scale invariant and formed in a similar fashion to braid bars in non-jökulhlaup braided rivers. Post-flood fragmentation and reworking of the bars consistently increased the length-width ratio of preserved bar fragments from approximately two and one half to over five. These observations increase our understanding of the preservation potential and final form of jökulhlaup deposits and provide the basis for an improved model for the recognition of jökulhlaup deposits in the geomorphological and sedimentary record. Article in Journal/Newspaper glacier Iceland University of Chester: Chester Digital Repository Skeiðarársandur ENVELOPE(-17.370,-17.370,63.848,63.848) Skeiðarárjökull ENVELOPE(-17.208,-17.208,64.056,64.056) Skeiðará ENVELOPE(-16.916,-16.916,63.784,63.784) Géomorphologie : relief, processus, environnement 22 1 51 60 |
institution |
Open Polar |
collection |
University of Chester: Chester Digital Repository |
op_collection_id |
ftchesteruniv |
language |
English |
topic |
Fluvial geomorphology Iceland Braided river Jokulhlaup Proglacial |
spellingShingle |
Fluvial geomorphology Iceland Braided river Jokulhlaup Proglacial Marren, Philip M. Bar deposition in glacial outburst floods: scaling, post-flood reworking, and implications for the geomorphological and sedimentary record |
topic_facet |
Fluvial geomorphology Iceland Braided river Jokulhlaup Proglacial |
description |
The appearance of a flood deposit in the geomorphological and sedimentary record is a product of the both the processes operating during the flood, and those that occur afterwards and overprinting the deposit with a record of ‘normal’ processes. Nearly half of the total discharge of the November 1996 jökulhlaup on Skeiðarársandur was discharged through the Skeiðará river. The flood deposits have been extensively reworked since, up until 2009 when the channel was abandoned, effectively leaving the Skeiðará as a terrace, when retreat of Skeiðarárjökull directed meltwater to the adjacent Gígjukvísl river system. This paper describes the creation and modification of jökulhlaup barforms in the Skeiðará river, relating the changes to post-flood fluvial processes and glacier retreat. Large compound bars formed from the amalgamation of unit bars up to 1.5 km long. The location of the compound bars was governed by the macro-scale topography of the flood channel, and their size by upstream channel width in accordance with bar-scaling theory. Jökulhlaup bars are therefore scale invariant and formed in a similar fashion to braid bars in non-jökulhlaup braided rivers. Post-flood fragmentation and reworking of the bars consistently increased the length-width ratio of preserved bar fragments from approximately two and one half to over five. These observations increase our understanding of the preservation potential and final form of jökulhlaup deposits and provide the basis for an improved model for the recognition of jökulhlaup deposits in the geomorphological and sedimentary record. |
author2 |
University of Chester |
format |
Article in Journal/Newspaper |
author |
Marren, Philip M. |
author_facet |
Marren, Philip M. |
author_sort |
Marren, Philip M. |
title |
Bar deposition in glacial outburst floods: scaling, post-flood reworking, and implications for the geomorphological and sedimentary record |
title_short |
Bar deposition in glacial outburst floods: scaling, post-flood reworking, and implications for the geomorphological and sedimentary record |
title_full |
Bar deposition in glacial outburst floods: scaling, post-flood reworking, and implications for the geomorphological and sedimentary record |
title_fullStr |
Bar deposition in glacial outburst floods: scaling, post-flood reworking, and implications for the geomorphological and sedimentary record |
title_full_unstemmed |
Bar deposition in glacial outburst floods: scaling, post-flood reworking, and implications for the geomorphological and sedimentary record |
title_sort |
bar deposition in glacial outburst floods: scaling, post-flood reworking, and implications for the geomorphological and sedimentary record |
publisher |
GFG |
publishDate |
2016 |
url |
http://hdl.handle.net/10034/605920 https://doi.org/10.4000/geomorphologie.11262 |
long_lat |
ENVELOPE(-17.370,-17.370,63.848,63.848) ENVELOPE(-17.208,-17.208,64.056,64.056) ENVELOPE(-16.916,-16.916,63.784,63.784) |
geographic |
Skeiðarársandur Skeiðarárjökull Skeiðará |
geographic_facet |
Skeiðarársandur Skeiðarárjökull Skeiðará |
genre |
glacier Iceland |
genre_facet |
glacier Iceland |
op_relation |
http://geomorphologie.revues.org/11262 Marren, P. M. (2016). Bar deposition in glacial outburst floods: scaling, post-flood reworking, and implications for the geomorphological and sedimentary record. Géomorphologie: relief, processus, environnement, 22(1), 51-60. DOI:10.4000/geomorphologie.11262 doi:10.4000/geomorphologie.11262 http://hdl.handle.net/10034/605920 1957-777X Géomorphologie : relief, processus, environnement |
op_rights |
http://creativecommons.org/licenses/by-nc-nd/4.0/ |
op_rightsnorm |
CC-BY-NC-ND |
op_doi |
https://doi.org/10.4000/geomorphologie.11262 |
container_title |
Géomorphologie : relief, processus, environnement |
container_volume |
22 |
container_issue |
1 |
container_start_page |
51 |
op_container_end_page |
60 |
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1766009786325794816 |