The Great Geoadvent: Door 14

The slides formed due to the overlying weight of the lava flows (a total of 24 flows, approximately 300m thick), weighing down on the weaker Jurassic sedimentary rocks. Under the pressure, the Jurassic rocks sheared along the N-S faults and huge blocks slid seawards along a rotational glide plane.

At the Quirang, five successive movements have been identified, extending over 2km from the scarp slope to the coast. Although features such as the Storr and the Quirang are currently stable, other areas remain active.

The sedimentary sequences at Trotternish comprise Middle and Upper Jurassic clays, shales and sandstones. Bearreraig Bay offers an excellent opportunity to examine exposures of Middle Jurassic sedimentary rock sequences.

Text: ScottishGeology.com

Image: Scarp slope and rotated blocks at the Quirang (© Liz Mickiewicz)