Assessment of doline geometry using geophysics on the Quercy plateau karst (South France)

Abstract

In the protection of karstic aquifers, the role played by dolines is of interest as these shallow structures can be preferential infiltration pathways for groundwater recharge. In this study, three depressions in South France (Orniac, Lot) were identified and characterized using combined geophysical methods. Apparent conductivity mapping allows precise definition of dolines corresponding to topographic depressions. It also reveals other dolines that are hidden by soil cover. Electrical resistivity and seismic refraction tomography provide detailed cross-sections. Even though the dolines studied are close one to another, they exhibit great variability in shape and content. Moreover, time-lapse data show that the most saturated regions are on the edges of the first doline. Such information helps to evaluate human impacts and forecast potential groundwater contamination.

The application of GPR and ERI in combination with exposure logging and retrodeformation analysis to characterize sinkholes and reconstruct their impact on fluvial sedimentation

“…Gutiérrez et al, 2014). Most investigations dealing with sinkhole characterization using subsurface methods have focussed on collapse sinkholes underlain by cavernous carbonate bedrock, and utilize near-surface geophysical methods in combination with geotechnical boreholes (van Schoor, 2002;Zhou et al, 2002;Kruse et al, 2006;Valois et al, 2011;Festa et al, 2012;Nouioua et al, 2013;Youssef et al, 2013). Most investigations dealing with sinkhole characterization using subsurface methods have focussed on collapse sinkholes underlain by cavernous carbonate bedrock, and utilize near-surface geophysical methods in combination with geotechnical boreholes (van Schoor, 2002;Zhou et al, 2002;Kruse et al, 2006;Valois et al, 2011;Festa et al, 2012;Nouioua et al, 2013;Youssef et al, 2013).…”

Dissolution rates of subsoil limestone in a doline on the Akiyoshi-dai Plateau, Japan: An approach from a weathering experiment, hydrological observations, and electrical resistivity tomography

“…For example, Nyquist et al (2007) indicated that a soil-bedrock interface provides resistivity of 1000 Ω•m on a karst terrain in eastern Pennsylvania. Valois et al (2011) also interpreted a layer with 1000 Ω•m resistivity as clayey sediment that filled a bedrock depression in a karst region in SW France.…”

Morphometric analysis of karst depressions on a mediterranean karst massif

“…Dolines play an important role in karst hydrogeology as they are often preferential infiltration pathways for groundwater recharge (Valois et al . ). Furthermore, the spatial distribution of dolines can provide very valuable information on neotectonics when appropriate methods of analysis are employed (Faivre and Reiffsteck ).…”

“…Although the structure of doline filling can be investigated by geophysical methods (Valois et al . ), the usual morphometric analysis only involves the depressions themselves (number, spatial location and pattern, orientation, depth, size, shape and altitude above sea level) and this information can be easily obtained from a number of different sources (Wu et al . ).…”