Shetland Islands

Shetland's complex and varied geo-diversity consists largely of metamorphic rocks, mainly of sedimentary origin altered by heat and pressure as the Caledonian Mountains were built, overlain by sedimentary and volcanic rocks which formed towards the end of that orogeny. In places the underlying basement of Precambrian gneiss (almost 3 billion years old) can be seen. North-east Shetland contains an ophiolite -ocean crust caught up in the continental collisions which formed Pangaea. The landscape has been sculpted by rivers, glaciers and the sea. Major landforms survive from before the last Ice Age. Though signs of glacial erosion are clear, some peat deposits survive from the last interglacial warm period. Shetland is sinking and shows geomorphological features of a recently drowned coastline. Exposed cliffs up to 370 metres high contrast with a gentler "inner"
coast of flooded valleys where rising sea level has created sand and shingle beaches, bars and tombolos.

Dromos