Low‐Frequency Induced Polarization of Porous Media Undergoing Freezing: Preliminary Observations and Modeling

Coperey, Antoine; Revil, A.; Abdulsamad, F.; Stutz, Benoı̂t; Duvillard, P.A; Ravanel, Ludovic

doi:10.1029/2018jb017015

Cited by 28 publications

(104 citation statements)

References 69 publications

(108 reference statements)

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“…Below freezing conditions, the water content of the liquid water is changing with the temperature according to a freezing curve. Duvillard et al () and Coperey et al () used an exponential freezing curve for the volumetric water content θ ( T ) written as

θ ((), T) = ({, \begin{array}{l} ((), ϕ - θ_{r}) \exp ((), - \frac{T - T_{F}}{T_{C}}) + θ_{r}, T \leq T_{F} \\ ϕ, T > T_{F} \end{array}),

which has the advantage to only require three parameters, T F (the liquidus or freezing point), T C (a characteristic temperature), and θ r (the residual water content).…”

Section: Complex Conductivity Of Rocksmentioning

confidence: 99%

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Complex Conductivity of Graphitic Schists and Sandstones

et al. 2019

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Spectral induced polarization spectra were carried out on three graphitic schists and two graphitic sandstones. The microstructural arrangement of graphite of two graphitic schists was studied with thin sections using transmitted and reflected light optical and electron microscopic methods. Chemical maps of selected areas confirm the presence of carbon. The complex conductivity spectra were measured in the frequency range 10 mHz to 45 kHz and in the temperature range +20 °C down to −15 °C. The measured spectra are fitted with a double Cole‐Cole complex conductivity model with one component associated with the polarization of graphite and the second component associated with the Maxwell‐Wagner polarization. The Cole‐Cole exponent and the chargeability are observed to be almost independent of temperature including in freezing conditions. The conductivity and relaxation time are dependent on the temperature in a predictable way. As long as the temperature decreases, the electrical conductivity decreases and the relaxation time increases. A finite element model is able to reproduce the observed results. In this model, we consider an intragrain polarization mechanism for the graphite and a change of the conductivity of the background material modeled with an exponential freezing curve. One of the core sample (a black schist), very rich in graphite, appears to be characterized by a very high conductivity (approximately 30 S/m). Two induced polarization profiles are discussed in the area of Thorens. The model is applied to the chargeability data to map the volumetric content of graphite.

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θ ((), T) = ({, \begin{array}{l} ((), ϕ - θ_{r}) \exp ((), - \frac{T - T_{F}}{T_{C}}) + θ_{r}, T \leq T_{F} \\ ϕ, T > T_{F} \end{array}),

which has the advantage to only require three parameters, T F (the liquidus or freezing point), T C (a characteristic temperature), and θ r (the residual water content).…”

Section: Complex Conductivity Of Rocksmentioning

confidence: 99%

“…Below freezing conditions, the water content of the liquid water is changing with the temperature according to a freezing curve. Duvillard et al (2018) and Coperey et al (2019) used an exponential freezing curve for the volumetric water content θ(T) written as…”

Section: Influence Of Temperature and Permafrostmentioning

confidence: 99%

Complex Conductivity of Graphitic Schists and Sandstones

et al. 2019

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“…The soil freezing curve can be related to the characteristics of the pore size distribution like the capillary pressure curve (Spans & Baker, ). In freezing conditions and accounting for the salt segregation effect, the electrical conductivity of the porous material is (Coperey et al, )

σ ((), T) = σ (T_{0}) ([], 1 + α_{T} (T - T_{0})),

where m (dimensionless) corresponds to the porosity exponent of Archie's law and σ ( T 0 ) denotes the conductivity (in S/m) at the reference temperature T 0 (=25 °C). While not apparent in equation , this model comprises both a conductivity contribution in the pore space and a surface conductivity contribution associated with electrical double layer (and therefore related to the cation exchange capacity [CEC] of the material).…”

Section: Electrical Conductivity Versus Temperaturementioning

confidence: 99%

“…The soil freezing curve can be related to the characteristics of the pore size distribution like the capillary pressure curve (Spans & Baker, 1996). In freezing conditions and accounting for the salt segregation effect, the electrical conductivity of the porous material is (Coperey et al, 2019)…”

Section: Electrical Conductivity Versus Temperaturementioning

confidence: 99%

“…Electrical conductivity tomography has been recently used to image permafrost in the shallow subsurface (e.g., Scott et al, 1990;Kneisel, 2006;Magnin et al, 2015). This has prompted the recent development of an improved physics-based petrophysical model, beyond the classical Archie's law, to connect electrical conductivity to temperature (e.g., Coperey et al, 2019;Duvillard et al, 2018). Such model needs to be further tested.…”

Section: Introductionmentioning

confidence: 99%

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Electrical Conductivity Versus Temperature in Freezing Conditions: A Field Experiment Using a Basket Geothermal Heat Exchanger

Coperey

Revil

Stutz

2019

Geophysical Research Letters

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We use a basket geothermal heat exchanger during 518 hr to freeze a portion of soil. This field experiment is monitored using time lapse electrical conductivity tomography and a set of 47 in situ temperature sensors. A frozen soil core characterized by negative temperatures and low conductivity values (<10 −3 S/m) develops over time. A petrophysical model describing the temperature dependence of the electrical conductivity in freezing conditions is applied to the field data and compared to two laboratory experiments performed with two core samples from the test site. The results show that this petrophysical model can be used to interpret field measurements bridging electrical conductivity to temperature and liquid water content. Plain Language SummaryIn order to better understand the evolution of permafrost (spatial extent, temperature, and liquid water content distributions), we can use time lapse electrical conductivity tomography. The electrical conductivity of a soil is influenced by water and ice contents, temperature, salinity of the pore water, and the cation exchange capacity of the material. We test a physics-based relationship connecting temperature, ice content, and electrical conductivity. This relationship is tested on two core samples and compared with field observations during a in-situ test experiment. In this experiment, we generated a frozen soil core using a geothermal heat exchanger, and at the same time, we recorded the temperature and electrical conductivity distributions. We found a good consistency between the field data and the model, which means that from the distribution of the electrical conductivity of the frozen soil, we are able to recover its temperature.

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Glacier, permafrost and thermokarst interactions in Alpine terrain: Insights from seven decades of reconstructed dynamics of the Chauvet glacial and periglacial system (Southern French Alps)

Cusicanqui

Bodin

Duvillard

et al. 2023

Earth Surf Processes Landf

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This study analyses the long‐term dynamics in the Chauvet glacial and periglacial system (southern French Alps) over seven decades (1948–2020), where several lake outburst floods have been documented since 1930. To accurately describe and explain the complex dynamics of this site, our multidisciplinary approach combines (1) photogrammetry of historical aerial photographs and modern high‐resolution satellite and UAV images, (2) geophysical surveys and (3) geomorphological mapping. We provide evidence for spatial and functional interactions between glacial and periglacial features, especially in the lower sector where different landforms with variable ice‐ and debris‐content and specific dynamics are interplayed. We found the highest thinning rates on ice‐rich terrain located in the central part of the valley bottom, which, together with bedrock morphology, most probably determine the location of the thermokarst. We also documented an overall acceleration of the creeping of the landforms after the 2000s, with a flow direction largely oriented towards the thermokarst depression. The outburst water flowed through a conduit whose successive opening and closure seem to mainly depend on the rate of lateral convergence of left‐ and right‐hand landforms and on the rate of ice melting (and roof collapse) along the conduit walls. Today, the site of Chauvet still represents a potential hazard for the region due to the large water storage capacity (up to 180 000 ± 450 m3) and the development of a predominantly bucket shape in the thermokarst sector.

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Low‐Frequency Induced Polarization of Porous Media Undergoing Freezing: Preliminary Observations and Modeling

Cited by 28 publications

References 69 publications

Complex Conductivity of Graphitic Schists and Sandstones

Complex Conductivity of Graphitic Schists and Sandstones

Electrical Conductivity Versus Temperature in Freezing Conditions: A Field Experiment Using a Basket Geothermal Heat Exchanger

Glacier, permafrost and thermokarst interactions in Alpine terrain: Insights from seven decades of reconstructed dynamics of the Chauvet glacial and periglacial system (Southern French Alps)

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