Modification of the land topography during glacial maximums due to the lithospheric flexure, temptative reconstructions of the southern North Sea landscapes during the Elsterian
Tunnel valleys have long fascinated the geoscientists by their scale and the consequent intensity of the sedimentary processes necessary to their formation. The filling of tunnel valleys in the southern North Sea is mainly made of clinoforms prograding north. A new sedimentological model has been de...
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ftcopenhagenunip:oai:pure.atira.dk:publications/07a0cb54-8b16-4295-9bd9-5283ff84339c 2023-05-15T16:41:27+02:00 Modification of the land topography during glacial maximums due to the lithospheric flexure, temptative reconstructions of the southern North Sea landscapes during the Elsterian Moreau, Julien Le Pourhiet, Laetitia Grappe, Benjamin Huuse, Mads Gibbard, Philip L 2015-06 https://curis.ku.dk/portal/da/publications/modification-of-the-land-topography-during-glacial-maximums-due-to-the-lithospheric-flexure-temptative-reconstructions-of-the-southern-north-sea-landscapes-during-the-elsterian(07a0cb54-8b16-4295-9bd9-5283ff84339c).html eng eng info:eu-repo/semantics/restrictedAccess Moreau , J , Le Pourhiet , L , Grappe , B , Huuse , M & Gibbard , P L 2015 , ' Modification of the land topography during glacial maximums due to the lithospheric flexure, temptative reconstructions of the southern North Sea landscapes during the Elsterian ' , 31st IAS Meeting of Sedimentology , Krakow , Poland , 22/06/2015 - 25/06/2015 . conferenceObject 2015 ftcopenhagenunip 2021-09-23T17:42:05Z Tunnel valleys have long fascinated the geoscientists by their scale and the consequent intensity of the sedimentary processes necessary to their formation. The filling of tunnel valleys in the southern North Sea is mainly made of clinoforms prograding north. A new sedimentological model has been developed, stating that the incision and the filling of the valleys are separate in times and from distinct processes. The erosion surface and consequently the tunnel valleys peculiar incision geometry are preserved after ice recession, forming sediment traps. The infill is interpreted as proglacial for the newly observed south-dipping clinoforms and postglacial for the north-dipping clinoforms onlapping the later. The north-dipping clinoforms are interpreted to be formed within a large deltaic system associated with the Rhine-Meuse river(s). The delta was probably infilling a lake containing 100's of m overdeeps (the underfilled tunnel valleys). The presence of clinoforms 50-80 m above the valley shoulders indicates the potential depth of the lake. However, remains of the regionally extensive lake are elusive and seldom preserved onshore. We have hypothesised that the depression hosting the lake was controlled by the lithospheric flexure which is present only during the glacial maximums and consequently difficult to pinpoint by only analysing today’s topography. In this depositional system, a competition exists between one of the biggest river of Europe facing ice sheets and the proglacial supply, generating a very intricate stratigraphy. We intend to solve part of the problem by numerically reconstructing the local landscape with the ice sheet and its isostatic depression. This allows to locate potential depocenters and lake thresholds/spillways to better understand the river migration and the position of the lacustrine systems. The Elsterian reconstructed landscape is unexpected since we show that the orientation of the slopes are locally reversed and the altitudes were drastically different between glacial maximums and interglacial times. Conference Object Ice Sheet University of Copenhagen: Research |
institution |
Open Polar |
collection |
University of Copenhagen: Research |
op_collection_id |
ftcopenhagenunip |
language |
English |
description |
Tunnel valleys have long fascinated the geoscientists by their scale and the consequent intensity of the sedimentary processes necessary to their formation. The filling of tunnel valleys in the southern North Sea is mainly made of clinoforms prograding north. A new sedimentological model has been developed, stating that the incision and the filling of the valleys are separate in times and from distinct processes. The erosion surface and consequently the tunnel valleys peculiar incision geometry are preserved after ice recession, forming sediment traps. The infill is interpreted as proglacial for the newly observed south-dipping clinoforms and postglacial for the north-dipping clinoforms onlapping the later. The north-dipping clinoforms are interpreted to be formed within a large deltaic system associated with the Rhine-Meuse river(s). The delta was probably infilling a lake containing 100's of m overdeeps (the underfilled tunnel valleys). The presence of clinoforms 50-80 m above the valley shoulders indicates the potential depth of the lake. However, remains of the regionally extensive lake are elusive and seldom preserved onshore. We have hypothesised that the depression hosting the lake was controlled by the lithospheric flexure which is present only during the glacial maximums and consequently difficult to pinpoint by only analysing today’s topography. In this depositional system, a competition exists between one of the biggest river of Europe facing ice sheets and the proglacial supply, generating a very intricate stratigraphy. We intend to solve part of the problem by numerically reconstructing the local landscape with the ice sheet and its isostatic depression. This allows to locate potential depocenters and lake thresholds/spillways to better understand the river migration and the position of the lacustrine systems. The Elsterian reconstructed landscape is unexpected since we show that the orientation of the slopes are locally reversed and the altitudes were drastically different between glacial maximums and interglacial times. |
format |
Conference Object |
author |
Moreau, Julien Le Pourhiet, Laetitia Grappe, Benjamin Huuse, Mads Gibbard, Philip L |
spellingShingle |
Moreau, Julien Le Pourhiet, Laetitia Grappe, Benjamin Huuse, Mads Gibbard, Philip L Modification of the land topography during glacial maximums due to the lithospheric flexure, temptative reconstructions of the southern North Sea landscapes during the Elsterian |
author_facet |
Moreau, Julien Le Pourhiet, Laetitia Grappe, Benjamin Huuse, Mads Gibbard, Philip L |
author_sort |
Moreau, Julien |
title |
Modification of the land topography during glacial maximums due to the lithospheric flexure, temptative reconstructions of the southern North Sea landscapes during the Elsterian |
title_short |
Modification of the land topography during glacial maximums due to the lithospheric flexure, temptative reconstructions of the southern North Sea landscapes during the Elsterian |
title_full |
Modification of the land topography during glacial maximums due to the lithospheric flexure, temptative reconstructions of the southern North Sea landscapes during the Elsterian |
title_fullStr |
Modification of the land topography during glacial maximums due to the lithospheric flexure, temptative reconstructions of the southern North Sea landscapes during the Elsterian |
title_full_unstemmed |
Modification of the land topography during glacial maximums due to the lithospheric flexure, temptative reconstructions of the southern North Sea landscapes during the Elsterian |
title_sort |
modification of the land topography during glacial maximums due to the lithospheric flexure, temptative reconstructions of the southern north sea landscapes during the elsterian |
publishDate |
2015 |
url |
https://curis.ku.dk/portal/da/publications/modification-of-the-land-topography-during-glacial-maximums-due-to-the-lithospheric-flexure-temptative-reconstructions-of-the-southern-north-sea-landscapes-during-the-elsterian(07a0cb54-8b16-4295-9bd9-5283ff84339c).html |
genre |
Ice Sheet |
genre_facet |
Ice Sheet |
op_source |
Moreau , J , Le Pourhiet , L , Grappe , B , Huuse , M & Gibbard , P L 2015 , ' Modification of the land topography during glacial maximums due to the lithospheric flexure, temptative reconstructions of the southern North Sea landscapes during the Elsterian ' , 31st IAS Meeting of Sedimentology , Krakow , Poland , 22/06/2015 - 25/06/2015 . |
op_rights |
info:eu-repo/semantics/restrictedAccess |
_version_ |
1766031880746958848 |