Tag Archives: borehole logging

Detecting Radioactive Anomalies

The low penetrating power of alpha and beta particles make them unlikely to be detected during field surveys. Instead, most radiometric surveys concentrate on detecting gamma rays. The low attenuation rate of gamma rays passing through air make both ground … Continue reading

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Detecting Density Anomalies

Gravity field surveying is a passive technique to detect gravity anomalies. Gravity is a global field that always points vertically down, with anomalies caused by very small variations in density of the underlying materials. A gravity base station measures the … Continue reading

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Detecting Porosity & Permeability

Effective porosity can be measured with electromagnetic induction probes. Hydraulic conductivity can be measured in-situ by observing water-level fluctuations in drill-holes. For a system at equilibrium, the system needs to be disturbed to produce fluid flow by either pumping water … Continue reading

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Detecting Physical Properties (Fieldwork)

Geophysical field surveys are used to investigate the subsurface. Geophysics may utilize passive techniques, measuring and mapping changes in the ambient field, or as active techniques that measures how the geological environment responds to an input signal. In either instance, … Continue reading

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Accretionary Wedge #61: Geo-jobs!

For October’s Accretionary Wedge, I asked what you did in your geoscience job. Martin Bentley¬†works in a¬†small geotechnical engineering company in South Africa, where he does a lot of borehole logging fieldwork, along with report creation and administration. The Gallivanting … Continue reading

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