Читать книгу The Westweg. Through Germany's Black Forest онлайн

9 страница из 45

While the Westweg does not compete for thrill and adventure with more alpine routes, its quieter, bucolic charms are seductive to those who are romantics at heart.

Typical Black Forest farmhouse (Stage 11B)

Geology

Geologically speaking, the mountains of the Black Forest are quite old. The bedrock, consisting of granite and gneiss, originated from volcanic activity some 200 million years ago. Variegated sandstone deposits, known as Bunter, which can mostly be seen in the northern parts, have built up through the eons. Thick layers of calciferous material (Muschelkalk and Keuper) around the southern fringes of the massif bear witness to an age when the region was covered by an arm of the Tethys Ocean and prehistoric corals populated this warm-water sea.

Prior to the Eocene epoch the Black Forest and the Vosges Mountains were part of the same tectonic plate, but due to the enormous pressures exerted on the earth crust during the formation of the Alps, the plate was stretched and pulled in opposite directions, which caused it to thin and eventually to crack. In a process that has lasted millions of years and is still in progress (at a rate of about 0.1mm per year), the ‘graben’ has sunk by about 4000m. At the same time the broken-off edges of the plates have lifted up, bringing ancient bedrock of granite and gneiss to the surface, while softer layers of Bunter, Keuper and Muschelkalk have eroded. The debris has collected in the plain and built up layer upon layer of sediments that have filled the fissure, which is why today there is no 4000m-deep ‘Grand Canyon’ between France and Germany.