Saturday, November 07, 2009
Raised sea stacks and river valleys on Jura's SW coast
The SW coast of Jura that faces the Sound of Islay has a very complex structure which reveals several past beach levels. Above the current beach there are numerous sea stacks and the base of a cliff which were cut when sea levels were higher.
About 10,000 years ago the beach was at the top of the cliff line. The weight of the ice sheet caused the Earth's crust under Scotland to sink into the magma below. As the ice melted the land started to rise and is still rising today. Meltwater from the retreating glaciers has cut steep V shaped ravines through the cliff line below the raised beaches. If these valleys had been cut by glaciers they would have been U shaped.
The tide had now picked up to a very pleasant 10km/hour and we were ably to relax and enjoy the view knowing we would make Port Askaig and the ferry in plenty of time.
We started a ferry glide across the Sound of Islay once we approached the small Carragh an t-Sruith lighthouse. It has a white flash every 3 seconds.