A methodology for wavelength dispersive electron probe microanalysis of unpolished silicate minerals

Abstract

Evaluation of mineral compositions is a widely used approach in resource exploration strategies where preparation time and cost may prove to be an important factor. In research institutes it is highly beneficial to determine the major element composition of minerals prior to their destructive analysis for trace elements and radiogenic isotopic ratios thus allowing a comprehensive interpretation of mineral petrogenesis. For the analysis of unique and small (submilligram) samples, avoiding sample loss is a key issue in ultimately producing high quality geochemical data. Consequently here we evaluate the precision and accuracy of electron probe microanalysis of unpolished garnet, olivine, orthopyroxene and clinopyroxene grains by comparison of analyses performed on polished thin sections of the same minerals. By utilizing a protocol that focuses on flat mineral surfaces, rejects analyses with low totals (