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TitleBorehole electrical resistivity, Vars-Winchester esker aquifer, Ontario
LicencePlease note the adoption of the Open Government Licence - Canada supersedes any previous licences.
AuthorOldenborger, G AORCID logo
SourceGeological Survey of Canada, Open File 8904, 2022, 44 pages, Open Access logo Open Access
PublisherNatural Resources Canada
Documentopen file
Mediaon-line; digital
RelatedThis publication is related to Electrical resistivity surveys, Vars-Winchester esker aquifer, Ontario
File formatpdf
AreaEmbrun; South Nation River
Lat/Long WENS -75.3192 -75.2931 45.3108 45.2722
Subjectshydrogeology; surficial geology/geomorphology; geophysics; Nature and Environment; Science and Technology; sediments; eskers; gravels; sands; clays; silts; soils; shales; groundwater resources; aquifers; boreholes; geophysical surveys; geophysical logging; resistivity logging; electrical resistivity; induced polarization; petrophysics; models; modelling; lithology; hydraulic conductivity; anisotropy; Vars-Winchester Esker Aquifer; Phanerozoic; Cenozoic; Quaternary
Illustrationstables; location maps; satellite images; geophysical logs; profiles; plots
ProgramGroundwater Geoscience Archetypal Aquifers of Canada
Released2022 06 30
Electrical resistivity and induced polarization surveys were conducted for a portion of the Vars-Winchester esker aquifer system near Embrun, Ontario. Resistivity data were acquired within boreholes as 1D logs, along the surface as 2D profiles, and from surface-to-borehole as 3D volumes. Borehole logs and pseudo-logs of electrical resistivity and chargeability from these surveys are compared to borehole geophysical logs, lithological logs, and hydraulic conductivity measurements collected at the study site. The resistivity records are in nominal agreement with electromagnetic induction logs of apparent resistivity, but there are significant differences attributed to scale and an anisotropy factor of approximately 2. Estimates of petrophysical model parameters and surface conductivity derived using the borehole fluid conductivity logs are not reliable. However, the borehole induction logs and pseudo-logs recovered from 1D, 2D, and 3D surveys all exhibit some separability of resistivity in terms of lithology that can be used for geological classification, and some correlation of resistivity with hydraulic conductivity that can be used for prediction away from the boreholes. Fidelity may be limited to the approximate distinction of aquifer versus aquiclude, particularly for the lowest-resolution 2D surface surveys.
Summary(Plain Language Summary, not published)
Geophysical surveys measuring electrical properties of the ground were conducted for a portion of the Vars-Winchester esker aquifer system near Embrun, Ontario. The measured electrical properties of resistivity and chargeability are compared to supporting data including borehole observations of geology and aquifer properties (porosity, hydraulic conductivity). Resistivity appears dependent on measurement scale and anisotropy (preferential flow of electrical current in the horizontal direction), but can be used for geological classification and prediction of hydraulic conductivity. Fidelity may be limited to the approximate distinction of aquifer versus aquiclude.

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