Bottom valley peat deposits from the river Somme basin: a record of the climatic and anthropogenic impacts on fluvial environments during the last 15 ka - Archive ouverte HAL Accéder directement au contenu
Communication Dans Un Congrès Année : 2022

Bottom valley peat deposits from the river Somme basin: a record of the climatic and anthropogenic impacts on fluvial environments during the last 15 ka

Résumé

Although the Somme valley (Northern France) is well known for its quaternary alluvial terraces system and the precision of its chronostratigraphic and chronocultural framework, its valley floor sequences are much less known. The research potential on the peaty valley bottoms of the Somme and its tributaries is still very important beyond the work carried out in the decades 1990-2000’s (Antoine & Ducrocq, 1997; Antoine, 1997; Antoine et al., 2012). Principally composed of large peaty accumulations, the Lateglacial and Holocene deposits form one of the largest alkaline peatland systems in north-west Europe. These valley bottom peat sequences, up to 8 meters thick, transcribe the variations in the peat formation-accumulation dynamics and bear witness to the palaeoenvironmental and climatic changes of at least the last 14,500 years. Following the recognition of the international importance of the peat system by the "Ramsar" certification of the valley in 2017 (framework set by the intergovernmental Convention on Wetlands, 1971) and in parallel with a European project for the restoration of peatlands (Life Anthropofen, EC Program), a new research dynamic has been implemented. For the first time, the peat is the core of the investigations in order to accurately characterise the conditions of its development and degradation. Here we present the first results of this research based on a 600 meters long high-resolution stratigraphic transect of the Somme valley (60 auger boreholes and corings up to 9 meters deep), completed by a set of thirty 14C dating. This approach will be completed in the near future by bio-indicators (pollens, malacofauna, ancient environmental DNA, diatoms, and plants macroremains) and geochemical analysis in order to provide a detailed reconstruction of the valley palaeoenvironments since about 15 ka and be able to evidence the impact of both the climate and human activities on the peaty environments.
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Dates et versions

hal-04472574 , version 1 (22-02-2024)

Identifiants

  • HAL Id : hal-04472574 , version 1

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Chloé Garcia, Boris Brasseur, Pierre Antoine. Bottom valley peat deposits from the river Somme basin: a record of the climatic and anthropogenic impacts on fluvial environments during the last 15 ka. Quaternaire 13, AFEQ et Université de Strasbourg, 2022, Strasbourg (67), France. ⟨hal-04472574⟩
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