Development and application of high-resolution petrography on resin-impregnated Holocene peat columns to detect and analyse tephras, cryptotephras, and other materials

We describe the potential for high-resolution detection, observation and chemical analysis of tephras and cryptotephras in freeze-dried and resin-impregnated peat sections. Special attention is drawn to tephra grain alteration products, sensitive to standard lab treatment, but preserved using an impregnation technique developed here. Resulting blocks and thin sections provide a continuous archive of tephras that can be investigated through a wide range of non-destructive techniques encompassing polarising and fluorescence microscopy, scanning electron microscopy with/without elemental analysis, and XRF-based core scanning.