The applications of reactor thermal and epithermal neutron activation analysis (NAA) to geological materials are reviewed. These include the historical development of radiochemical (destructive) (RNAA) and instrumental (non-destructive) (INAA) methods, the counting systems, epithermal neutron activation. Special attention is given to reference materials and the place of NAA in the firmament of geoanalytical techniques for their certification and characterization. Literature references useful in NAA of geological materials are listed.
Fresh and aged samples of foraminifera and red algae from two different climatic areas (the Great Barrier Reefs of Australia and the northwestern Mediterranean Sea) were analyzed by non-destructive thermal and epithermal neutron activation for some traces and rare-earth elements (REE). Mechanisms were tentatively proposed to explain the measured distributional differences: iron scavenging effect, microbial intervention at given stages of very early diagenesis, feeding behaviour of organisms... REE and traces follow increases of iron content during biodiagenesis; this process does not apparently originate discrimination in the distributional pattern of REE. Eu negative and Ce positive anomalies were recorded in both types of organisms; these anomalies were explained by bioprocesses.
The different important stages of the development of proton induced X-ray emission (PIXE) spectrometry utilised with success
since 1976 at Liège University are outlined. The methodological efforts (irradiation, target preparation, calibration, matrix
effect corrections) to improve quantitative trace element analysis are emphasized. Examples of applications in geological,
biomedical and environmental sciences are selected in order to illustrate the potential of the technique in these fields.
Authors:A. Brunfelt, I. Roelandts, and E. Steinnes
Three procedures are outlined for the determination of rare-earth elements in geological materials. The irradiation of the
samples is carried out by either thermal or epithermal neutrons. Two of the methods, one of which is especially suitable for
ultramafic rocks are based on radiochemical separations, while in the third method non-destructive analysis is applied to
apatites. The γ-ray activity measurements are performed by means of coaxial Ge(Li)-detectors.
Authors:I. Roelandts, G. Robaye, G. Weber, J. Delbrouck, and J. Duchesne
More than 200 specimens from different occurrences of the Rogaland igneous complex and surrounding granulite facies metamorphic rocks (S. W. Norway) have been analysed by a direct non-destructive proton induced gamma-ray emission (PIGE) technique. The fluorine contents vary from <25 ppm to 3500 ppm. There is a good correlation between the concentration of fluorine and that of phosphorus for igneous rocks, suggesting a control of apatite on the F content. In metamorphic rocks, amphibole and biotite besides apatite are the principal cencentrators of fluorine indicating that fluorine in the system is controlled by granulite facies metamorphism conditions.
Authors:I. Roelandts, G. Robaye, G. Weber, P. Aloupogiannis, and J. Delbrouck-Habaru
Fifteen geochemical reference samples /GRS/ issued from the Geological Survey of Japan have been analyzed by an automated proton induced -ray emission /PIGE/ method for fluorine. Results of determinations are reported. Values are given for many GRS that have not previously been analyzed for fluorine.