Thursday, 9 June 2016
Geology near the Pier
Something like 60 million years ago, the limestone was intruded by molten rocks associated with the Ardnamurchan volcano. A sheet of this - the browner rock - pushed its way into the limestone. To some extent it followed the natural lines of weakness in the limestone, along its bedding planes, but just here it split in two, into an upper sheet marked 'S1' and a lower sheet marked 'S2' which cuts across the limestone beds before continuing to follow them. Neither of these sheets can have been particularly hot as the limestone shows no signs of baking where the igneous rock is in contact.
Since that time, the great pile of rock which buried this feature has been worn away, much of it by the ice sheets which covered the area until about 10,000 years ago. The sea has recently removed more, exposing the structure in a low cliff.