On the Rocks
- 5 mins
The rocks that we see on Islay give us access to a mind-blowing and grandiose history of the planet. The timescales we’re dealing with are the last 1.8 billion years - reaching halfway back to the very formation of the earth. There is evidence on Islay of unrecognisable continents, past glaciations, the beginning of life on earth, and the vestiges of the much more recent ice age just a few thousand years ago.
We’re interested in the geology for three reasons. One, its direct bearing on agriculture - the different soils that the bedrock gives us affect the successful raising of barley here. Two, what the geology means for the water we use to make whisky. Three, it deepens our understanding of Islay's terroir - several rock types and aeons collide here.
SIMPLIFIED MAP - BRITISH GEOLOGICAL SOCIETY
Loch Gruinart and Loch Indaal are two shallow sea lochs that divide Islay from the north and south. They were formed along a branch of the Great Glen Fault that divides Scotland, the same fault system that creates the famous national landmarks of Loch Ness and Glencoe as it travels from north-east to south-west. It also produces the minor earth tremors that occasionally rattle our windows! Along the faultline in the middle of Loch Indaal, around 470 million years ago, two super continents collided after the closing of the ancient Iapetus sea which separated them. Scotland had been on one super-continent, England on the other.
You can see the drama written into the tilted rocks in the Port Ellen area. David Webster, who had a career in the oil industry before retiring to Islay - where he has built a house behind the distillery and written a book of geological walks - remarks, “If they drained Loch Indaal, they’d probably find dinosaur fossils down there off Port Charlotte! The scallop dredgers have turned up ammonites from the same era…”