The landscape in Denmark was mostly shaped by large glaciers in the last of the four ice ages, we know of in Denmark.

In the last ice age, which lasted from around 100,000 to 8,000 BC most of the country was covered by ice. The movements of the ice during this period created the landscape, and also central and north Jutland, even though certain local topographical features reflect earlier ice ages and subterranean movements.

The ice age has left its mark in various ways, for instance in the way floodwaters created by melting ice shaped the landscape. However, the coastline has been shaped by the power of the sea in more recent times, while wind and weather have contributed to coastline curves.

The effects can be seen in the noticeable glacial moraines at Hundborgbuen, at Hanklit, in the northern part of Mors and from Fur to the area near Randers. They were formed by ice flowing from the north and northeast. In Vendsyssel, you can see traces of the ice from the north where floes were pushed up on Lønstrup Klint. The straightening of the hills west of the river Bangsbo and in Hirtshals can probably be attributed to the pressure of ice from the north. 

However, the geological development in Jutland still persists. For instance, Grenen in Skagen (the Spit) is moving northeastwards at a rate of 10 metres a year. Yet in 2001, it grew by 100 metres – so in theory, the Spit will reach Sweden at some point. Although the flow from the Baltic, which pushes the water northwards along the Swedish west coast, will curve the sand strongly northwards. You can read more about Skagen in the local Nature Centre.

In the Cretaceous period, around 135-65 million years ago, sea levels rose all around the world, and the whole of Denmark was covered by shallow seawater. The climate was warm and with probably very little rainfall. Armoured algae lived in the sea and when these died their shells sank to the bottom, creating huge deposits of calcium in the sea, resulting in white chalk. Fossils of larger creatures such as sea urchins, mussels and brachiopods can also be found in these deposits. Moreover, Fungi lived at the bottom of the sea at that time.

Chalk from the Cretaceous period can be seen in places like Svinkløv, Hanstholm, Erslev, Daugbjerg and Mønsted. At Erslev chalkpits there are geological layers of chalk and limestone from the age when dinosaurs became extinct, which marks the boundary between the Cretaceous and Mesozoic eras 65 million years ago. At the base of the chalkpit, fossils of e.g. sea urchins have been found.

At Daugbjerg and Mønsted visitors can go underground and see the chalk. Mønsted chalk mines have the largest number of underground chalk caves in the world and the mine passageways in Daugbjerg Chalkmines are 35 km long.

Moler can only be found around the Limfjord, it was deposited in the Tertiary period around 65 -2 million years ago.

Moler is made up of the shells of siliceous algae, diatoms, which lived in the sea, and when they died their shells dropped to the seabed. Moler is rich in fossilised plants, insects, fish and other vertebrae. The Moler Museum on Mors has a magnificent collection of 55 million year old fossils and a workshop where visitors can investigate the moler.

In addition to fossils, there are plenty of dark volcanic ash layers in the moler, revealing 179 layers of ash from eruptions from the volcanoes close to the moler sea. These ash layers correspond with a volcano field in Rende in Norway, which was a break point when Europe and North America drifted apart when the Atlantic opened up.
Tertiary period volcanoes, of the same type as we see in Iceland today, were found here.