Tag Archives: physical properties

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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Characterizing Radioactivity

Detection of radioactivity depends on the type of radiation being targeted. Geiger Counters Gieger counters are short tubes filled with a low-pressure mixture of gas with electrodes maintained at a large potential difference. When radiation entered through the window, the … Continue reading

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Radioactivity of Geological Materials

Primeval elements with long half-lives such as potassium (40K), thorium (232Th), and uranium (235U, 238U produce elements with shorter half-lives as part of the decay process. Other primeval elements such as calcium (48Ca), vanadium (50V), and nickel (58Ni) are either … Continue reading

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Radioactivity

Some elements are naturally radioactive, releasing alpha particles, beta particles, or gamma radiation as they decay to more stable elements. The decay in a fixed period of time is proportional to the number of unstable atoms, with exponential decay dictating … 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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Characterizing Density

Measuring density is a simple method of measuring the mass, measuring the volume, then calculating the density as mass divided by volume. Dry density, wet density, and grain density can all have geotechnical utility. All three are calculated by dividing … Continue reading

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Density of Geological Materials

The density of a rock is closely tied to its mineralogy. Sedimentary rocks have a lower density than igneous rocks, with most sandstones having a density close to the density of quartz (ρ = 2.65 g/cm3), suggesting that they are … Continue reading

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Density

Density (ρ) is the mass (m) of a material divided by its volume (V), given in units of mass per unit volume (kg/m3): ρ = m/V The density of a material is a function of the density of the individual … 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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Characterization of Porosity & Permeability

Porosity and permeability are closely related, so it is unsurprising that measuring the properties share common techniques that involve determining interconnected pore volume. Porosity Porosity (n) is measured as the ratio of the volume of voids within a material to … Continue reading

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