Greenland ice cores show evidence of a large volcanic eruption in 1642 ± 5 BCE, which was suggested as being associated with Santorini. However, volcanic ash retrieved from an ice core does not match the expected Santorini fingerprint. The late Holocene eruption of Mount Aniakchak, a volcano in Alaska, is now believed to be the source of the minute shards of volcanic glass in the Greenland ice core.