Glacial erratics on and around Rügen

An erratic is usually defined (in Germany) as an individual block of rock lying on the surface of the land which has a volume of at least one cubic metre and which was transported by a glacier to its present site during the ice age.

Until the 19th century large erratics were used as quarries, in order to produce construction material for monuments (e. g. in 1854 the Prussia Columns near Neukamp and Groß Stresow or for the Ernst Moritz Arndt Tower on the Rugard, for coastal and harbour defences, cobblestones and millstones.

On the one hand, Rügen (especially the Jasmund peninsula) was the ice divide between the Belt and the Oderstrom glaciers of the Weichselian glaciation and, as a result, a band of debris typical of a medial moraine developed here.

On the other hand, erratics have been exposed by coastal erosion (especially by the action of breakers) and may be found on beaches at the foot of sea cliffs.

Such erratics on Rügen, which are made of crystalline and metamorphic rock, that have a minimum volume of 10 m³ belong to the legally protected geotopes on the island.