Readjustments of a sinuous river during the last 6000 years in northwestern Europe (Cher River, France): From an active meandering river to a stable river course under human forcing
Anaëlle Vayssière
(1, 2)
,
Cyril Castanet
(3)
,
Emmanuèle Gautier
(3)
,
Clément Virmoux
(3)
,
Thomas Depret
(4)
,
Emmanuel Gandouin
(5)
,
Anne-Lise Develle
(6)
,
Fatima Mokadem
(3)
,
Ségolène Saulnier-Copard
(3)
,
Pierre Sabatier
(6)
,
Nathalie N. Carcaud
(7)
1
UP1 -
Université Paris 1 Panthéon-Sorbonne
2 LIENSs - LIttoral ENvironnement et Sociétés
3 LGP - Laboratoire de géographie physique : Environnements Quaternaires et Actuels
4 EVS - Environnement, Ville, Société
5 IMBE - Institut méditerranéen de biodiversité et d'écologie marine et continentale
6 EDYTEM - Environnements, Dynamiques et Territoires de Montagne
7 ESO - Espaces et Sociétés
2 LIENSs - LIttoral ENvironnement et Sociétés
3 LGP - Laboratoire de géographie physique : Environnements Quaternaires et Actuels
4 EVS - Environnement, Ville, Société
5 IMBE - Institut méditerranéen de biodiversité et d'écologie marine et continentale
6 EDYTEM - Environnements, Dynamiques et Territoires de Montagne
7 ESO - Espaces et Sociétés
Cyril Castanet
- Fonction : Auteur
- PersonId : 753558
- IdHAL : cyril-castanet
- ORCID : 0000-0001-5840-4815
Emmanuèle Gautier
- Fonction : Auteur
- PersonId : 182453
- IdHAL : emmanuele-gautier
- ORCID : 0000-0001-5725-3576
- IdRef : 050339575
Clément Virmoux
- Fonction : Auteur
- PersonId : 11011
- IdHAL : clement-virmoux
- ORCID : 0000-0002-0413-786X
Thomas Depret
- Fonction : Auteur
- PersonId : 184830
- IdHAL : thomas-depret
- ORCID : 0000-0001-6491-6112
- IdRef : 236191985
Emmanuel Gandouin
- Fonction : Auteur
- PersonId : 18846
- IdHAL : emmanuel-gandouin
- ORCID : 0000-0001-6970-9630
- IdRef : 075962721
Anne-Lise Develle
- Fonction : Auteur
- PersonId : 4269
- IdHAL : anne-lise-develle
- ORCID : 0000-0003-2824-4106
- IdRef : 253119383
Fatima Mokadem
- Fonction : Auteur
- PersonId : 747464
- IdHAL : fatima-mokadem
Ségolène Saulnier-Copard
- Fonction : Auteur
- PersonId : 183632
- IdHAL : segolene-saulnier-copard
- ORCID : 0000-0002-3462-0940
- IdRef : 170096734
Pierre Sabatier
- Fonction : Auteur
- PersonId : 8569
- IdHAL : pierre-sabatier
- ORCID : 0000-0002-9620-1514
- IdRef : 112919405
Nathalie N. Carcaud
- Fonction : Auteur
- PersonId : 982905
- ORCID : 0000-0001-5971-1411
Résumé
Palaeomeanders are characteristic features of meandering river floodplains. Some were abandoned several millennia ago and can be used as evidence for past fluvial patterns. Despite many observations of changes undergone by meandering rivers, little is known about long-term morphological adjustment of meanders. This paper reports on investigations conducted in two reaches located in the middle valley of the Cher River (northwestern Europe, France) to examine the readjustments of lowland meanders during the second half of the Holocene. The aim of our study was to provide new insights into the complex dynamics that control low-energy meandering rivers. LiDAR DEM spatial analyses coupled with geophysical surveys and observations of sediments enabled the identification and dating of thirteen palaeomeanders embedded in coarse sediments (sand and gravel) while the whole floodplain is covered by silty overbank deposits. Sedimentological, geochemical and pollen analyses combined with radiocarbon and OSL dating allowed us to reconstruct the chronology of the cutoff and the filling of palaeochannels. No palaeochannels older than ca 6000 yr cal. BP, and no palaeochannels younger than the eleventh-thirteenth centuries cal. AD were identified. This allowed us to distinguish two periods of meandering processes. (1) Our observations demonstrate the multi-millennia persistence of an active meandering pattern in a context of land use changes (ca 6000 yr cal. BP-eleventh-thirteenth centuries cal. AD). The preserved mobility of the river can be mainly interpreted as the result of the low cohesiveness of the bank material. Too few fine sediments were delivered during the proto-historical and historical periods to help stabilize the river course. (2) Following the eleventh-thirteenth centuries cal. AD, the fluvial system underwent a laterally stable phase. The many medieval and modern hydraulic engineering works reduced the specific stream power and prevented lateral erosion. The drastic decrease in the river's capacity to generate new meanders resulted in the disappearance of floodplain lakes and loss of habitat diversity.
Format du dépôt | Fichier |
---|---|
Type de dépôt | Article dans une revue |
Résumé |
en
Palaeomeanders are characteristic features of meandering river floodplains. Some were abandoned several millennia ago and can be used as evidence for past fluvial patterns. Despite many observations of changes undergone by meandering rivers, little is known about long-term morphological adjustment of meanders. This paper reports on investigations conducted in two reaches located in the middle valley of the Cher River (northwestern Europe, France) to examine the readjustments of lowland meanders during the second half of the Holocene. The aim of our study was to provide new insights into the complex dynamics that control low-energy meandering rivers. LiDAR DEM spatial analyses coupled with geophysical surveys and observations of sediments enabled the identification and dating of thirteen palaeomeanders embedded in coarse sediments (sand and gravel) while the whole floodplain is covered by silty overbank deposits. Sedimentological, geochemical and pollen analyses combined with radiocarbon and OSL dating allowed us to reconstruct the chronology of the cutoff and the filling of palaeochannels. No palaeochannels older than ca 6000 yr cal. BP, and no palaeochannels younger than the eleventh-thirteenth centuries cal. AD were identified. This allowed us to distinguish two periods of meandering processes. (1) Our observations demonstrate the multi-millennia persistence of an active meandering pattern in a context of land use changes (ca 6000 yr cal. BP-eleventh-thirteenth centuries cal. AD). The preserved mobility of the river can be mainly interpreted as the result of the low cohesiveness of the bank material. Too few fine sediments were delivered during the proto-historical and historical periods to help stabilize the river course. (2) Following the eleventh-thirteenth centuries cal. AD, the fluvial system underwent a laterally stable phase. The many medieval and modern hydraulic engineering works reduced the specific stream power and prevented lateral erosion. The drastic decrease in the river's capacity to generate new meanders resulted in the disappearance of floodplain lakes and loss of habitat diversity.
|
Titre |
en
Readjustments of a sinuous river during the last 6000 years in northwestern Europe (Cher River, France): From an active meandering river to a stable river course under human forcing
|
Auteur(s) |
Anaëlle Vayssière
1, 2
, Cyril Castanet
3
, Emmanuèle Gautier
3
, Clément Virmoux
3
, Thomas Depret
4
, Emmanuel Gandouin
5
, Anne-Lise Develle
6
, Fatima Mokadem
3
, Ségolène Saulnier-Copard
3
, Pierre Sabatier
6
, Nathalie N. Carcaud
7
1
UP1 -
Université Paris 1 Panthéon-Sorbonne
( 7550 )
- 12 place du Panthéon, 75231 Paris Cedex 05
- France
2
LIENSs -
LIttoral ENvironnement et Sociétés
( 154635 )
- Bâtiment Marie Curie Avenue Michel Crépeau 17 042 La Rochelle cx1 - Bâtiment ILE 2, rue Olympe de Gouges 17 000 La Rochelle
- France
3
LGP -
Laboratoire de géographie physique : Environnements Quaternaires et Actuels
( 1343 )
- 2 rue Henri Dunant
94320 Thiais
- France
4
EVS -
Environnement, Ville, Société
( 145345 )
- 18 Rue Chevreul
69362 LYON CEDEX 07
UMR 5600
- France
5
IMBE -
Institut méditerranéen de biodiversité et d'écologie marine et continentale
( 188653 )
- Aix Marseille Université, Campus Etoile, Faculté St-Jérôme case 421 Av. . escadrille Normandie-Niemen 13397 MARSEILLE CEDEX 20
- France
6
EDYTEM -
Environnements, Dynamiques et Territoires de Montagne
( 20150 )
- Université de Savoie, Campus scientifique, 73376 Le Bourget du Lac cedex
- France
7
ESO -
Espaces et Sociétés
( 59373 )
- France
|
Langue du document |
Anglais
|
Vulgarisation |
Non
|
Comité de lecture |
Oui
|
Audience |
Internationale
|
Date de publication |
2020-08
|
Nom de la revue |
|
Page/Identifiant |
107395
|
Domaine(s) |
|
Référence interne |
|
Mots-clés |
en
Palaeochannel, Meanders, Floodplain, Channel mobility, Holocene, Cher River
|
DOI | 10.1016/j.geomorph.2020.107395 |
UT key WOS | 000589917400007 |
Origine :
Fichiers produits par l'(les) auteur(s)
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