Dr Arjan Dijkstra Testing Samples (IMAGE) University of Plymouth Caption Dr Arjan Dijkstra subjected samples to detailed chemical analysis using X-ray fluorescence (XRF) spectrometry, and by dissolving them in acid conduct a more intensive isotopic analysis. Credit University of Plymouth Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.