Doleriteis an igneous rock, which means that it was created from magma from beneath the Earth’s crust. Around 300 million years, magma forced its way up through cracks in the surrounding host rocks. Kinnekulle has a relatively small capof doleriteleft, which explains why from a distance the mountain has the characteristic conical outline that reminds us of a volcano.
Around Högkullen you can also see signs of the last ice age, known as drumlins. A drumlin is an elongated ridge made up of moraine and gravel that were deposited underneath the ice. The ridges of drumlins are oriented in line with the direction the ice was moving, and this makes it possible to chart the flow of the ice by mapping the drumlins across the landscape.