Development of techniques for high-resolution spatially-resolved elemental analysis in materials of interest in luminescence dating

Abstract

A series of analytical techniques have been developed to characterise the surface distribution of elements in a number of materials of archaeological interest, in support of current and future research in luminescence dating techniques.

Under certain circumstances, sample heterogeneity, with respect to naturally occurring radionuclides, may significantly reduce the levels of accuracy associated with experimentally determined luminescence dates.

The aim of this thesis is to develop a series of high-resolution, spatially resolved techniques to assess and quantify the degree of matrix (material fabric) radionuclide heterogeneity present in a number of archaeological materials.

Digital analysis and mineralogical staining techniques were combined to provide initial data regarding matrix heterogeneity and the distribution patterns of potassium-bearing minerals and in some cases, provided data that were comparable to those derived from SEM-EDX analyses.

Alpha autoradiographic techniques using solid state nuclear track detectors (CR-39) were applied initially to map localised differences in surface alpha activity, and were subsequently developed to provide semi-quantitative data about the concentration of alpha emitters present, and by association, the likely concentrations of uranium and thorium.

Micro-sampling techniques were developed to produce material for instrumental analysis (ICP-MS and AAS), to provide quantitative information about the concentrations of uranium, thorium and potassium in the areas of interest, highlighted by the application of the aforementioned techniques.

The techniques were successfully applied in a number of case studies, providing both quantitative and qualitative information relating to material characteristics with respect to luminescence dating techniques.