SCIENTISTS at the University of York have completed an 11-year study to accurately date locations from the last ice age by using fossilised snail shells.

Dr Kirsty Penkman and Prof Matthew Collins, from the university, took part in the largest ever programme to date the Quaternary period, which stretches back nearly three million years and redeveloped a 40-year-old technique of using the proteins found in fossil snail shells to date sites.

Prior to the study, it was difficult to age the deposits from glaciers and hence also to establish their response to climate change. This newly developed method makes it possible to not only link these deposits to climate change, but also to compare the responses with those of plants and animals.

The research looks at the proteins preserved in the fossil opercula, the little “trapdoor” that a snail uses to shut itself inside its shell.

“The amino acids are securely preserved within the opercula. This protects the protein from external environmental factors, so the extent of degradation allows us to identify the age of the samples,” said Dr Penkman. “In essence it is a protein time capsule.”

The method proved highly reliable, with more than 98 per cent of samples yielding useful results, making it the largest study of this kind ever and giving it enormous international scope.