Ice cores are cylinders of ice (approximately 10cm wide) drilled out of an ice sheet or glacier. On the East Antarctic Ice Sheet, these can be up to 3.6km deep. They represent frozen time capsules that allow scientists to reconstruct the past evolution of the climate and the environment going back almost one million years.
Trapped dust particles and ionic species can be analysed, providing information about past atmospheric conditions such as circulation patterns, sea-ice cover, anthropogenic pollution and volcanic eruptions. In particular, ash layers preserved in the ice not only inform about volcanic activity, they can also be dated to help determine the chronology of the ice.
This image shows a section of ice core from James Ross Island, Antarctica, from a depth of 279m. The vertical dark stripe, visible in the centre, is a layer of volcanic ash embedded in the ice.
Dr Emilie Capron
British Antarcic Survey