Abstract
Volcanic sediments are generally difficult to date using luminescence dating methods, but many important archaeological and palaeoanthropological sites are located in volcanic regions. Here we present an improved dating procedure for grains with composite mineralogies deposited at Liang Bua, the type locality of Homo floresiensis in Indonesia, using the post-infrared infrared stimulated luminescence (pIRIR) signal. Individual mineral grains that emit detectable pIRIR signals are composed of a range of feldspar varieties, quartz, clay minerals, heavy minerals and volcanic glass, rendering the isolation of individual potassium-rich feldspar grains infeasible. We investigate the luminescence behaviour of these composite mineral grains in detail, including their thermal stability, anomalous fading and dose-response characteristics. A standardised growth curve is developed to enable more time-efficient measurements, together with a ‘micro-aliquot’ approach in which each hole