Holocene vegetation changes through Lac Ledro sediments (Trentino, Italy).
Sébastien Joannin
(1, 2, 3)
,
Boris Vannière
(1)
,
Didier Galop
(4)
,
Michel Magny
(1)
,
Adrian Gilli
(5)
,
Emmanuel Chapron
(6)
,
Stefanie Wirth
(7)
,
Flavio Anselmetti
(7)
,
Marc Desmet
(8)
1
LCE -
Laboratoire Chrono-environnement (UMR 6249)
2 PEPS - PaleoEnvironnements et PaleobioSphere
3 MSHE - Maison des Sciences de l'Homme et de l'Environnement Claude Nicolas Ledoux (UAR 3124)
4 GEODE - Géographie de l'environnement
5 D-ERDW - Department of Earth Sciences [Swiss Federal Institute of Technology - ETH Zürich]
6 ISTO - Institut des Sciences de la Terre d'Orléans
7 Geological Institute [ETH Zürich]
8 ACCES-INRP
2 PEPS - PaleoEnvironnements et PaleobioSphere
3 MSHE - Maison des Sciences de l'Homme et de l'Environnement Claude Nicolas Ledoux (UAR 3124)
4 GEODE - Géographie de l'environnement
5 D-ERDW - Department of Earth Sciences [Swiss Federal Institute of Technology - ETH Zürich]
6 ISTO - Institut des Sciences de la Terre d'Orléans
7 Geological Institute [ETH Zürich]
8 ACCES-INRP
Sébastien Joannin
- Fonction : Auteur
- PersonId : 19986
- IdHAL : sebastien-joannin
- ORCID : 0000-0001-8345-9252
- IdRef : 11417038X
Boris Vannière
- Fonction : Auteur
- PersonId : 170991
- IdHAL : boris-vanniere
- ORCID : 0000-0002-6779-6053
- IdRef : 22094850X
Didier Galop
- Fonction : Auteur
- PersonId : 13698
- IdHAL : didier-galop
- ORCID : 0000-0003-1746-4760
- IdRef : 035586850
Michel Magny
- Fonction : Auteur
- PersonId : 5658
- IdHAL : michel-magny
- IdRef : 027001652
Emmanuel Chapron
- Fonction : Auteur
- PersonId : 173685
- IdHAL : emmanuel-chapron
- ORCID : 0000-0003-3661-0225
- IdRef : 05773691X
Résumé
Lake Ledro is part of the French program ANR LAMA (coordinators: M. Magny and N. Combourieu Nebout) which aims to link Holocene paleoenvironmental changes along a north-south transect in Italy. Lake Ledro (652 m a.s.l.; Trentino, north-eastern Italy) is the northward component of the transect. It is located on the southern slope of the Alps and its catchment area covers 131 km2 with mountains culminating at 1500-2000 m. A multi-proxy approach based on biotic and abiotic indicators (lake-level, palynology, geochemistry and geophysic) was developed from deep and littoral cores, including sediment sequences in Early and Middle Bronze Age lake-shore archaeological sites. We aim reconstructing paleoenvironmental changes resulting from both climate and anthropic influences trough the entire Holocene. A deep master core was built after extracting twin cores from a non disturbed sediment zone recognised by seismic-reflexion investigations. The age-depth model is based on 13 AMS 14C ages measured on terrestrial plant macrofossils and the mean temporal resolution for analyses is ca 60 years. Palynological study shows the usual vegetation succession for the southern slope of the Alps. During the first part of the Holocene, abrupt changes are observed in pollen assemblages in relation to changes in other proxies (XRF and Magnetic Susceptibility) and correlate with cold events associated to the deglaciation in the North-Atlantic area. Cool episodes corresponding to the PreBoreal Oscillation (ca 11.3 ka cal BP) and 8.2 ka event are respectively characterized by stopping afforestation and a strong development of Abies in the local ecosystem. During the second part of the Holocene, two declines of arboreal pollen abundance are observed in relation with occurrences in both cereal and anthropic pollen indicators. These two phases are confirmed by increase in soil erosion as indicated by abiotic proxies. They give evidence of two successive steps for human settlement (Early-Middle Bronze Age and Iron Age) separated by forest development. In addition, XRF data allow two successive distinct palaeohydrological periods to be recognized into the Holocene. Finally, comparison between littoral and deep cores reinforces our interpretation and helps to disentangle climate and anthropic influences on the Holocene environment in the Central Mediterranean region.
Format du dépôt | Notice |
---|---|
Type de dépôt | Communication dans un congrès |
Titre |
en
Holocene vegetation changes through Lac Ledro sediments (Trentino, Italy).
|
Résumé |
en
Lake Ledro is part of the French program ANR LAMA (coordinators: M. Magny and N. Combourieu Nebout) which aims to link Holocene paleoenvironmental changes along a north-south transect in Italy. Lake Ledro (652 m a.s.l.; Trentino, north-eastern Italy) is the northward component of the transect. It is located on the southern slope of the Alps and its catchment area covers 131 km2 with mountains culminating at 1500-2000 m. A multi-proxy approach based on biotic and abiotic indicators (lake-level, palynology, geochemistry and geophysic) was developed from deep and littoral cores, including sediment sequences in Early and Middle Bronze Age lake-shore archaeological sites. We aim reconstructing paleoenvironmental changes resulting from both climate and anthropic influences trough the entire Holocene. A deep master core was built after extracting twin cores from a non disturbed sediment zone recognised by seismic-reflexion investigations. The age-depth model is based on 13 AMS 14C ages measured on terrestrial plant macrofossils and the mean temporal resolution for analyses is ca 60 years. Palynological study shows the usual vegetation succession for the southern slope of the Alps. During the first part of the Holocene, abrupt changes are observed in pollen assemblages in relation to changes in other proxies (XRF and Magnetic Susceptibility) and correlate with cold events associated to the deglaciation in the North-Atlantic area. Cool episodes corresponding to the PreBoreal Oscillation (ca 11.3 ka cal BP) and 8.2 ka event are respectively characterized by stopping afforestation and a strong development of Abies in the local ecosystem. During the second part of the Holocene, two declines of arboreal pollen abundance are observed in relation with occurrences in both cereal and anthropic pollen indicators. These two phases are confirmed by increase in soil erosion as indicated by abiotic proxies. They give evidence of two successive steps for human settlement (Early-Middle Bronze Age and Iron Age) separated by forest development. In addition, XRF data allow two successive distinct palaeohydrological periods to be recognized into the Holocene. Finally, comparison between littoral and deep cores reinforces our interpretation and helps to disentangle climate and anthropic influences on the Holocene environment in the Central Mediterranean region.
|
Auteur(s) |
Sébastien Joannin
1, 2, 3
, Boris Vannière
1
, Didier Galop
4
, Michel Magny
1
, Adrian Gilli
5
, Emmanuel Chapron
6
, Stefanie Wirth
7
, Flavio Anselmetti
7
, Marc Desmet
8
1
LCE -
Laboratoire Chrono-environnement (UMR 6249)
( 57629 )
- 16, route de Gray - 25030 Besançon Cedex
- France
2
PEPS -
PaleoEnvironnements et PaleobioSphere
( 172603 )
- Campus de la Doua, Bâtiment GEODE 2 rue Raphaël Dubois 69622 Villeurbanne cedex
- France
3
MSHE -
Maison des Sciences de l'Homme et de l'Environnement Claude Nicolas Ledoux (UAR 3124)
( 2228 )
- 32-36, rue Mégevand 25030 BESANCON CEDEX
- France
4
GEODE -
Géographie de l'environnement
( 742 )
- 5 Allée Antonio Machado 31058 TOULOUSE CEDEX 1
- France
5
D-ERDW -
Department of Earth Sciences [Swiss Federal Institute of Technology - ETH Zürich]
( 102961 )
- Sonneggstrasse 5, 8092 Zürich, Schweiz
- Suisse
6
ISTO -
Institut des Sciences de la Terre d'Orléans
( 254028 )
- Projet I.S.T.E. 1A, rue de la Férollerie 45071 ORLEANS CEDEX 2
- France
7
Geological Institute [ETH Zürich]
( 219585 )
- Sonneggstrasse 5, 8092 Zürich
- Suisse
8
ACCES-INRP
( 106261 )
- France
|
Vulgarisation |
Non
|
Comité de lecture |
Oui
|
Actes |
Non
|
Invité |
Non
|
Langue du document |
Anglais
|
Audience |
Internationale
|
Titre du congrès |
EGU Natural and anthropogenic environmental change as evidenced in high-resolution continental archives (co-listed)
|
Date début congrès |
2010-05-02
|
Date fin congrès |
2010-05-07
|
Ville |
Vienne
|
Pays |
Autriche
|
Commentaire |
Poster
|
Domaine(s) |
|
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