Summary
In this talk, we will step onto a geological time machine, to visit, on a group of little uninhabited islands in the Inner Hebrides, evidence for the most extreme climate change in our planet’s history. The Garvellach Islands and Islay expose a magnificent section of the Port Askaig Formation deposited some 700 million years ago at a time of extreme world-wide glaciation (‘Snowball Earth’) which was far more severe than our current Ice Age. These rocks contain an extraordinary number of glacial features as well as recording the onset of the glaciation that defines the start of the Cryogenian Period of the Precambrian. The sequence appears to be unique and is a prime candidate for a global ‘golden spike’. The snowball earth concept will be discussed and how the succession here fits (or doesn’t) with this model. Life as we know it today radiated out from the very few survivors of this global climatic Armageddon.
