Speleogenetic reconstitution of a karst combining underground and surface geomorphology -implication for hydrology (Verneau, French Jura) - Archive ouverte HAL
Communication Dans Un Congrès Année : 2024

Speleogenetic reconstitution of a karst combining underground and surface geomorphology -implication for hydrology (Verneau, French Jura)

Résumé

The aim of our work is to propose a speleogenetic reconstitution of a karst network, combining two complementary morphological approaches from underground and surface data, in order to relate the speleogenesis model with the hydrogeological one. The study site is the underground karst network of Verneau (French Jura), which has the particularity of being almost completely penetrable and topographically recognized. The hydrosystem is characterized by 5 sinkholes draining the marly outcrops of the recharge area. First, the geometry of the underground network (orientation and organization of conduits) is characterized using the open-source software Karstnet. Second, a chronology of the network development is assessed by calculating the erosion time required to shape the surface forms of the marly sinkholes watersheds, identifying the erosion levels and estimating the eroded volumes using DTM data. Finally, the spatial variability of the water level dynamics along the conduit network is characterized using a comparative approach of the hydrological response recorded at 6 stations.The quantitative approach of the geometrical characterization of the underground network allows us to divide the Verneau into two downstream and upstream compartments with significantly different properties on conduit orientation and network organization. On the surface, we traced the erosion levels of each losing stream, then quantified the erosion time required to form the surface shapes. The information gathered is convergent, enabling us to propose a coherent model of speleogenesis of the Verneau underground network through the phases in which the surface network was captured during the Quaternary. The study of water level variations at different sites along the network showed that there is a spatial variability of the hydrological response, consistent with the morphological downstream/upstream compartmentalization identified in the speleogenesis model. Moreover, the comparative analysis enables us to date the compartments relatively well, to deduce the structural history of the Verneau network, and to relate it to its current hydrology. This work represents an initial approach to the development and structuration of karst aquifers in the Jura Mountains.
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Dates et versions

hal-04557246 , version 1 (26-04-2024)

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  • HAL Id : hal-04557246 , version 1

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Margot Vivier, Jean-Baptiste Charlier, Pauline Collon, Eglantine Husson, Stéphane Jaillet. Speleogenetic reconstitution of a karst combining underground and surface geomorphology -implication for hydrology (Verneau, French Jura). 4th Eurokarst Conference (EUROKARST 2024), EUROKARST, Jun 2024, Rome, Italy. ⟨hal-04557246⟩
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