Dr. Ai Nguyen, University of Queensland (IMAGE) University of Queensland Caption Dr Ai Nguyen performing column chemistry in UQ's world class Radiogenic Isotope Facility (School of Earth Sciences) to separate uranium and thorium isotopes in the coral samples. Credit Dr Tara Clark Usage Restrictions For use in association with this story 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.