Søndbjerg beach
Coastal cliff with deposits from the Miocene
Søndbjerg Beach is located on the east coast of Thyholm, about 1 km from the village of Søndbjerg.
The site is a coastal cliff that extends approximately 300 m along the coast. The layers in the cliff are exposed to varying degrees, but after major erosion events they can be clearly observed.
The layers consist primarily of deposits from the Miocene epoch, and illustrate the area's development from a marine environment to a floodplain as the coastline prograded across the area.
A large part of the strata series consists of fine-grained marine sand, which is deposited on the outer shoreline. This sand can be attributed to the Billund Formation (Hvidbjerg Member).
Elsewhere in the geopark, Billund sand is found at great depth - see Hygum Bakke , but at Søndbjerg the Miocene layers lie high, as they have been pushed up by the Uglev salt diapir - see Odby Klint .
The cliff also contains rhythmic layers of sand and clay, which were deposited in a tidal lagoon very similar to today's Nissum Fjord .
The dune sand rests partly on glacial deposits and partly on raised seabed. The glacial deposits can be observed in the cliff profile at the western boundary of the area at Græm Klint , where it is clearly evident that the glacial layers are covered by thick aeolian sand deposits.
The coastal dunes are located on a stretch of coastline that is undergoing erosion, and in several places along the West Coast there are active dunes with exposed sand surfaces.