Geology of the Nahe valley

400 million years ago, in the Devonian period, Europe was near the equator and the climate was warm. A shallow ocean with islands covered central Europe, in which Hunsrück formed a deeper basin of this ocean with a stable layering of water. The upper water layers were rich in oxygen and supportive to life, whereas the lower levels were poor in oxygen and poisoned by hydrogen sulfide. The remains of living organisms sank into the black mud and were quickly preserved by ferrous sulphide, which is why they have kept so well. In the Herrenberg slate quarry near Bundenbach a large number of world-renowned fossils were found that, when x-rayed, showed even the finest details. The rivers that flowed into the Devonian sea deposited large amounts of muddy sediment, sand, gravel and clay, which, due to pressure and heat over millions of years, became layers of stone and rock. In this way, depending upon the material and coarseness, slate, sandstone, and (with a high percentage of quartz grains) Taunus quartzite were created.

300 million years ago, at the end of the Carboniferous period, the Devonian layers of the Hunsrück were pushed together by massive pressure from southeast to northwest creating the Variszicum mountains (the northern chain). Together with the Hochwald, Idarwald, and Soonwald chains, a high mountain range was formed. The debris resulting from the erosion and weathering of this range was deposited in the basin on the south flank, building up the "Lower Rotliegende". After another rising of the mountains and sinking of the basin the process was repeated creating the "Upper Rotliegende". During the Permian period the formation of mountains was accompanied by strong volcanic activity on the southern fault of Hunsrück.

Photo: View from Ebernburg Castle over the wine village Ebernburg to the Rotenfels massif.