Product has been added to the basket

St Kilda

Outer Hebrides, Scotland

St Kilda

The stark islands of the St Kilda archipelago rise steeply out of the Atlantic Ocean, about 40 miles west of Harris in the Outer Hebrides. 

St Kilda

The largest island is Hirta, inhabited by a small population until 1930 and with the highest sea cliffs (430m) in the UK.

St Kilda is an eroded remanent of a Palaeogene volcanic centre that was active about 55 million years ago, part of a suite of central volcanoes associated with crustal rifting that accompanied the formation of the North Atlantic.

St Kilda

The islands are mostly formed by intrusive igneous rocks, typical of rocks formed underneath central volcanoes and exposed by erosion. 

The earlier part of the volcanic activity created a layered gabbro intrusion, which is was later cut by a granite intrusion.

There are also many smaller sheets and dykes that cut through the older rocks – erosion along these lines of weakness is responsible for some of the variety of coastal features including stacks, arches and the ledges utilised by nesting seabirds. 

St Kilda

The archipelago was recognised as a World Heritage site in 1986.

Text courtesy of Angus Miller, Scottish Geodiversity Forum

100 Great Geosites

Related Links

Images (Top to Bottom): 
  • Hirta, St Kilda © Mick Crawley (source Creative Commons Attribution-ShareAlike 2.0 license.
  • Ruined houses at Village Bay, St Kilda © Ian Mitchell (Source Creative Commons Attribution-ShareAlike 2.0 license.
  • Good exposure of Mullach Sgar Complex at west end of Village Bay © Rachel Wignall / Scottish Natural Heritage
  • Stac Lee from west © Rachel Wignall / Scottish Natural Heritage
Earth Science Week

ESW no date badge 2018
October 13 - 21
Theme: 'Earth Science in our lives'