The summit of the Clemensberg is embedded in the Niedersfeld high heath landscape of the Neuer Hagen nature reserve, a relic of former cattle farming in the high altitudes of the Rothaargebirge. From the summit, you have a good view of the landscape and a large diabase quarry. The boulders around the summit cross come from this quarry.
Geology: The Clemensberg is made up of hard and resistant diabase rock. At the time when the diabase was formed, a sea stretched across the entire area that is now the Sauerland. Large rivers transported erosion debris from a mainland far to the northwest, the Old Red continent, into this sea basin. Mainly clays and sands were deposited on the seabed, which solidified over time. Thin, basaltic lavas rose from the earth's mantle (from a depth of around 150 km) via fractures and penetrated the rock along bedding planes. On contact with the seawater, they quickly solidified. This lava, which turned to stone, is known as intrusive diabase. In the course of mountain formation 300 million years ago, these layers were then strongly constricted, folded and uplifted under high pressure. A mountain range was formed: the Rhenish Slate Mountains. This was subject to millions of years of weathering and erosion, resulting in the landscape we see today. The weathering-resistant diabase remained as evidence of volcanic activity between the clayey-sandy rock layers and today form the peaks of many mountains as hard rocks
.Age of the rocks: Lower Carboniferous period, around 320 million years before todayUse
: Due to its great hardness and resilience, diabase is mainly used as chippings and gravel in road construction, but also as hydraulic engineering stone. In the past, diabase was also used as a material for gravestones.