Ballentine lab (IMAGE) University of Oxford Caption Dr Anran Cheng (lead author, left) and Professor Chris Ballentine (right) preparing equipment for measurement of helium isotopes in geological samples. Credit: Sarah Hilton. Credit Dr Anran Cheng (lead author, left) and Professor Chris Ballentine (right) preparing equipment for measurement of helium isotopes in geological samples. Credit: Sarah Hilton. Usage Restrictions The image can be used if the credit is included. License Original 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.