The Roschertal owes its existence to a geological peculiarity. It is a breakthrough valley of the Mandau, which has cut through a basalt layer and underlying tertiary tuff layers. Such valleys are formed when a river erodes rock over long periods of time, while the surrounding area may rise or the water cuts deeper.
Geological development:
1. Tertiary deposits: In the Tertiary period (around 65 to 2.6 million years ago) the area was characterized by volcanic activity. Tuff - a rock made of volcanic ash - was deposited. Later, basalt flows poured over it and formed a resistant covering layer.
2. Cutting of the Mandau: The Mandau, a tributary of the Neisse, began to work its way through the harder basalt layer over time. Since basalt is much more resistant than the tuff underneath, the erosion process was uneven. The softer rock layers were eroded more quickly, so that the valley gradually deepened.
3. Formation of the breakthrough valley: As the rock was further eroded, the steep, wooded slopes of the Roschertal that are visible today were created. These reach heights of around 50 to 60 meters above the valley floor.
4. Late Pleistocene influence: During the ice ages, the landscape was further shaped when frost weathering and landslides affected the valley flanks. During this time, the Mandau transported more meltwater and debris, which caused the river to dig in further.
Special features today:
The Roschertal is not only a geologically interesting area, but also an example of the natural development of Upper Lusatia. The interplay of basalt and tuff layers gives the landscape a varied morphology. Erosion has created some bizarre rock formations, and the forest that has developed in the valley protects the loose rock layers from further erosion.
The fact that the Mandau has formed a breakthrough valley here also influences the water dynamics. The flow can vary greatly depending on the water level, which is noticeable in small cascades and whirlpools.
In summary, the Roschertal is a product of the volcanic past, fluvial erosion and ice age processes - an exciting geological formation that also offers an attractive landscape for hikers and nature lovers.