15e Congrès des Sédimentologistes Français – Projet AAP Montagne 2015

Source : Université Savoie Mont Blanc

Du 13 au 17 octobre 2015 s’est tenu le 15e Congrès français de sédimentologie à Chambéry.

Ce congrès biannuel de l’Association des sédimentologistes français (ASF) qui représente la plus grande manifestation francophone sur les sédiments a été organisé par l’Université Savoie Mont Blanc, l’Université Grenoble Alpes et le CNRS en collaboration avec de nombreux partenaires.

Ce projet fait partie des 11 projets de recherche menés dans le cadre de l’AAP Montagne 2015 : http://bit.ly/1TTbfbj

Suivez toute l’actualité de la recherche à l’USMB : http://bit.ly/1KYfjPM


Territorial practices, landscape dynamics and mobilities in a french mountain

Source : www.canal-u.tv


Anglais non sous-titré



Territorial practices, landscape dynamics and spatio-temporal mobilities in a french medium mountain : integrated approach combining archaeological and paleoecological inverstigations performed in the Cantal massif and the mount Lozère (French Massif Central). Philppe ALLÉE et Yannick MIRAS. In « La construction des territoires montagnards : exploitation des ressources et mobilité des pratiques », 2e International Workshop on archaeology of european mountain landscape, organisé par les laboratoires GEODE, FRAMESPA, GEOLAB et Chrono-Environnement. Université Toulouse 2-Le Mirail, 8-11 octobre 2009. [seconde journée].


Two integrated archaeological and palaeoenvironmental research programs have been carried out since 2000 in the French Massif Central at a high spatial and temporal resolution in order to achieve a better understanding of the environmental/anthropogenic interactions in different medium mountain ecosystems ranging from 1000 m to 1600 m a.s.l. from the Mid-Holocene to the end of Modern Times.


The data presented here offer the opportunity to examine the long term shaping of two different cultural landscapes. The first one is the volcanic southern “planèze” of the Plomb du Cantal, in the heart of the Massif Central, and whose continental climate is particularly harsh and where heavy snow and rainfall underlines a pronounced oceanic tendency. This zone is also characterized by rich and fertile volcanic soils, though no mineral resources (flint, ore) are available. The second one is the crystalline area of the Mont Lozère, in the east-southern Massif Central. Its mountain climate is noticeably influenced by Mediterranean conditions and mineral resources are abundant and consist mainly in silver. The strength of carrying the same pluridisciplinar approach in these two different socio-environmental contexts lies in providing a higher degree of landscape variabilities and a larger range of available natural resources. It allows thus a comparative reconstruction of the complex land-use models developed throughout the Holocene by human societies and the triggers of their dynamics (climate vs socioeconomic transformations). It better questions the heterogeneity and the complementarities in the management of these mountain spaces (agropastoralism, forest exploitation, coal production, and metallurgy).


Although alpine vegetation belt is totally absent in the whole French Massif central, the data presented argue in favour of gradual and differential altitudinal gradients of human practices which fluctuate throughout time, particularly the altitudinal limit for cereal growth and the summer grazing activity. Even if these medium mountain areas must be considered as complex landscapes shaped during a long term land-use history marked by important common thresholds, different chronological patterns and spatial land-use distribution start to be formulated at a micro-regional scale suggesting other gradient of explanation than altitude and, combining to cultural data (social, demographic, politic, system of commercial exchange, ritualistic and symbolic aspects etc.), explaining the construction of these mountain territories.



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Evolution of land use at lake St Point (Jura mountains) since the neolithic period

Source : www.canal-u.tv


Anglais non sous-titré


Evolution of Land use at lake St Point (Jura Mountains) since the neolithic Period : palynological and sedimentological analyses. Emilie GAUTHIER. In « La construction des territoires montagnards : exploitation des ressources et mobilité des pratiques, 2ème International Workshop on archaeology of european mountain landscape, organisé par les Laboratoires GEODE et TRACES (Toulouse) et le Centre d’Archéologie Préhistorique du Rhône aux Alpes (Valence, France). Université Toulouse II-Le Mirail, 8-11 octobre 2009. [Première journée.]

Lake St Point (850 m ASL.) is located in the central part of Jura Mountains. The vegetation surrounding the lake is represented by wood pastures. Pasture woodland is a very ancient form of land use, characterized by a mosaic landscape, from the open pasture to the closed forest. In the context of human impact on vegetation, the aim of this study is to investigate chronology and details of the transition between the original ecosystems to the sylvopastoral ecosystem.
The deepest part of Lake St Point was cored from a floating platform. Chronology of the sequence is based on 24 AMS radiocarbon dates spread over the upper 7 m of the core. Concerning the recent period, 137Cs measurements were processed on the 20 upper centimeters of the sequence. The first results confirm the high quality of the deep lacustrine records and their scientific interest. The sediment succession collected in Lake St Point reveals a stratigraphically continuous profile spanning the entire Holocene period, and showing particular sensitivity to Human impact on vegetation. Pollen analysis reveals the first human impact as soon as the early Neolithic period, around 5300 cal. BC. Then, first farmers disappear until 4000 cal. BC. From this period to the end of Bronze Age, a particular land use takes place. Distinct pulses of forest clearance as a result of human activity can be observed. Among anthropogenic indicators, peaks of Cerealia type are followed by the increase of open landscape herbs.
In a third phase, shrubs and light demanding trees (Juniperus, Acer…) develop in the clearance. Sedimentological analyses show that silicates and detrital carbonate fractions progressively increased, due to the erosion of soil. From the end of Bronze Age to the end of Iron Age, both Cerealia type and plants of open landscape curves increase and decrease together. This different signal suggests a new type of land use, with permanent fields. The Hallstatt period is characterized by regular human impacts while La Tène period correspond to a decline of agriculture. However, human pressure remains perceptible with regular clearance in the Fagus and Abies forest. Silicates content still increased while detrital carbonates input became steady due to a change in pedogenetic processes affecting thecatchment. he two last millennia have recorded the most important human impact: large »scale deforestation, especially during the Middle Ages, altered the vegetation cover drastically. Grassland became used more intensively and during the modern period, silicates and detrital carbonate decreased, probably due to wood pastures development.




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