LECTURE 10: RADIOMETRIC METHOD H. Saibi Dec. 11, 2015

Schematic illustration of the radiometric method

Exponential decay process

Interaction of g-rays with matter

Attenuation of g-rays of different initial energies by various materials encountered in the geological environment.

Changes in atomic number (Z) and neutron number (N) associated with radioactive decay.

Energy spectra of g-rays produced by the decay of the 3 main naturally occurring radioelements

Statistical measurement error versus the number of emission counts recorded

Examples of modern g-ray spectrometers

Fields of view

Factors contributing to the g-ray spectra measured in the field and the corrections applied to reduce the survey data

Radiometric data presented to highlight only anomalous responses.

Radioelement content of igneous rocks and selected minerals and ores.

Radioelement content of metamorphic rocks and selected minerals and ores.

Radioelement content of sedimentary rocks and selected minerals and ores.

The 238U decay series showing half-lives and potential mechanisms for disequilibrium within the series

Schematic illustration of near0-surface processes that affect radiometric responses.

Abundances of K, U, and Th compared for bedrock and adjacent overburden

Variations in radioelement concentrations in the soil/regolith profile

Summary of K and Th concentrations in the vicinity of the Goonumbla-North Parkes Cu-Au porphyry deposits.

Geochemical data from altered and unaltered rocks from the Waitekauri area

The Iron King Pb-Zn-Cu-Au-Ag sulphide deposit.

Schematic illustration of the radiation source areas of various terrain forms for ground radiometric measurements

Profiles of radiometric data and various channel ratios from the Uranium City area.

Radiometric data from the Yeelirrie calcrete U deposit.

Radiometric and magnetic data from the Waihi-Waitekauri epithermal Au-Ag field.

Data from the Flinders Ranges

Subsets of the radiometric data

Examples of g-logs and their relationship to lithology from a range of mineralised geological environments.

Self-Potential and g-logs through a coal-measured sequence.

g-logs through iron formations at Jimbledar in the Hamersley iron-ore province of Western Australia.