Evidence of Snowball Earth, with David Webster
18th January 2021
The ‘Snowball Earth’ deposits of Islay and the Garvellachs are one of the ‘51 Best Places to see Scotland’s Geology’. Together the islands record a thick, well-exposed, and complete section through a major glacial episode which is correlated with the global ‘Sturtian’ event that occurred some 720 million years ago. The Garvellachs section is proposed as a ‘golden spike’ to mark the definitive base of the Cryogenian Period of the Precambrian; and in northern Islay there are several candidates for a cap-carbonate which mark the termination of the glacial cycle.