Deglaciation of vosges gréseuses and paleoclimat reconstruction base on in situ produced beryllium-10 exposerent dating
National audience In the context of global ice retreat, studying glaciers and glacier responses to present and past climatic variations provides information to understand their long-term evolution. Alpine and Pyrenean glaciers have been the subject of paleoclimate studies but it is not the case of t...
Published in: | Quaternaire |
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Main Authors: | , , , , , , |
Other Authors: | , , , , , , , , , , , , , , , , , , , , , , |
Format: | Article in Journal/Newspaper |
Language: | French |
Published: |
HAL CCSD
2024
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Subjects: | |
Online Access: | https://hal.science/hal-04576226 https://doi.org/10.4000/quaternaire.19147 |
Summary: | National audience In the context of global ice retreat, studying glaciers and glacier responses to present and past climatic variations provides information to understand their long-term evolution. Alpine and Pyrenean glaciers have been the subject of paleoclimate studies but it is not the case of the Vosges Gréseuses (VG), a low to médium mountain range in northeastern France. This project focuses on the analysis of the palaeoglaciers of this area, where many landforms suggest the presence of ice during colder periods. We determined the locations of the paleoglaciers and mapped them by using the software ArcGIS and the tool “GlaRe” (Glacier Reconstructions Tools). We show that glaciers in the VG were not very extensive and did not exceed 45 m thick. We also dated moraines closest to the cirques using the cosmogenic 10Be and confirmed that glaciers were indeed present in this area during the Last Glacial Maximum (LGM) between 19.5 and 13.0 ka. Climatic reconstructions, obtained from Equilibrium Line Altitude (ELA), show that mean summer temperatures were between 1.8 and 2.4°C, considering precipitations equivalent to the current level. Glaciers retreated before the Younger Dryas (YD) due to their small sizes, which differentiates them from the Vosges Cristallines, where deglaciation occurred later. Finally, initial dating of the Rocher de Mutzig, one the highest point of the VG, shows that an ice cap probably covered the massif until 38.000 years ago. In a context of cold climatic episodes, it is interesting to link the glacial evolution and prehistoric population dynamics, that must have adapted to paleoclimatic conditions, closing of strategic paths and decrease of ressources. Face à la fonte généralisée des masses de glace, l'étude des glaciers et de leurs réponses aux variations climatiques présentes et passées peut fournir des informations nécessaires à la compréhension de leur évolution sur le long terme. Si les glaciers alpins et pyrénéens ont fait l'objet d'études paléoclimatiques, ce n'est pas le ... |
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