GEO Resources – providing Complete Geological solutions
GEO Resources provide a complete geological service. From initial investigative work and budget management to acquisition and processing, we manage the entire investigation, right through to project completion.
Our firm commitment to delivering a cost-effective, efficient and expert-led service for all our clients makes GEO Resources the perfect choice for your next project. GEO Resources assign experienced engineers to every job. They utilise the latest technology and high-quality equipment on-site, ensuring the best possible outcome for every geological operation.
- Surveys
- Budgeting
- Acquisition
- Project supervision
- Exploration programmes
- HSE audits & inspections
- Training and development
- Seismic data quality control
Our geological techniques
Sounding & Profiling Resistivity
Geophysical resistivity techniques are based on the response of the earth to the flow of electrical current.
With an electrical current passed through the ground and two potential electrodes to record the resultant potential difference between them, GEO Resources can obtain a direct measure of the electrical impedance of the subsurface material.
The resistivity of the subsurface, a material constant, is then a function of the magnitude of the current, the recorded potential difference, and the geometry of the electrode array. Depending upon the survey geometry, the data are plotted as 1-D sounding or profiling curves or in 2-D cross-sections in order to look for anomalous regions.
Resistivity measurements are associated with varying depths relative to the distance between the current and potential electrodes in the survey, and can be interpreted qualitatively and quantitatively in terms of a lithologic model of the subsurface.
Utilised across a range of environments and depths, the electrical resistivity technique of geophysical exploration is suitable for both soundings and profiling. This method is used to explore:
For further information on any of our surface geophysics solutions, or to speak to a member of our expert team,
call or email GEO Resources today.
Resistivity Imaging (Tomography)
Resistivity geophysical surveys measure variations in the electrical resistivity of the ground, by applying small electric currents across arrays of ground electrodes. This technology can be used by GEO Resources to obtain images of relatively static subsurface site conditions.
The survey data is processed to produce electrical resistivity tomographs using inversion algorithms. The resistivity sections are correlated with ground interfaces such as soil and fill layers or soil-bedrock interfaces, to provide engineers with detailed information on subsurface ground conditions.
Resistivity imaging, also known as electrical resistivity tomography (ERT) is a particularly useful survey method in clayey ground, where techniques such as Ground Penetrating Radar (GPR) are less effective. The method can also help to identify transitional boundaries in subsurface layers that can be difficult to detect using other geophysical methods and is a useful tool for locating deep seated sinkholes, mine workings and detection of metallic ore bodies.
Resistivity soundings, profiles and ERT are also used to assess the geometry of aquifers and their likely water quality. These tools are particularly useful in
locating water supplies.
Time-Domain Electromagnetic (TDEM) Soundings
Time-Domain Electromagnetic (TDEM) soundings are widely used by GEO Resources in exploration geophysics for mapping subsurface layers. TDEM is a relatively low cost, rapid, and noninvasive reconnaissance tool to locate potential water resources.
The TDEM method is well suited to near-surface hydrological studies as it can be used to differentiate between fresh, brackish, and saline water. It is used to investigate the electrical conductivity of the subsurface through measurements of electromagnetic field over time.
The characteristics of the TDEM responses of the earth due to a pulsed primary signal from a large wire square-loop laid on the ground surface yields information about the variations of the electrical conductivity with depth.
The conductivity of soils and rocks are controlled by mineralogy, clay content, water content, salinity, and porosity. Changes in the conductivity of soils and rocks produce variations in the electromagnetic signature.
A combination of existing well water quality measurements borehole data and surface TDEM can be used to accurately map the subsurface water resources with one caveat: a signal from clay can sometimes produce a response similar to water.
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