Schwäbisch-Fränkische Gäue

Gäu Plateaus

The Gäue or Gäulandschaften area extends in a strip from the Rhine in the south to the Main in the north, whereby the strip is very narrow in the south and widens in the north. The name is hardly known even to locals, which is probably also due to the ancient word Gau, which, on the one hand, refers to an administrative unit and on the other to agricultural land surrounded by higher forest areas. In the case of the Gäue, these are the Black Forest and the Odenwald, which are geologically lower but have a slightly higher sea level due to the dip of the strata. This is the Muschelkalk (Upper Triassic) and Lower Keuper strata, covered in large areas by loess and loess loam. Due to the fertile soil and the low location, it is geologically and climatically favoured and has been a preferred settlement area since the early Neolithic period.

Besides the Upper Jurassic of the RegionSchwäbische Alb (Swabian Jura) and the RegionFränkische Alb (Frankian Jura), the Muschelkalk is the main karstified bedrock in Germany. The Hohenlohe Plain is the largest German Muschelkalk (Middle Triassic) karst area. It belongs to the RegionSüddeutsche Schichtstufenlandschaft (South German Scarplands). However, the Muschelkalk does not form a large plateau like the Upper Jurassic of the Swabian Jura. Rather, it is intersected by a large number of rivers, resulting in the formation of many individual plateaus, which can be clearly distinguished both geographically and hydrologically. The rivers serve as KarstStream Channel during cave development, so that the cave levels are located at the former levels of the Kocher, Jagst, Tauber and Bühler rivers.

In much of the area, the Muschelkalk (Middle Triassic) is covered by a relatively thin layer of Keuper (Upper Triassic) sandstone (10-30 m thick). This does not interfere with karstification if the water can penetrate the cover layer at fractures and still reach the karstified rock. However, this naturally creates difficulties for exploration, since the caves are hidden under the Keuper sandstone, so to speak.

In the Muschelkalk, considerable progress has been made in recent years. The first large Muschelkalk cave to be discovered was the ShowcaveEberstadter Tropfsteinhöhle. In the meantime, however, several other extraordinarily large cave systems have been discovered, especially in the Schrozberger Schild plateau, west of Rothenburg o.d. Tauber. The Fuchslabyrinth has meanwhile been surveyed to 10 km, but has not yet been fully explored. Thus, for a time, it was even the longest cave in Germany, replacing the Salzgrabenhöhle in the Alps at that time.

The western border is the plateau of the Buntsandstein, lower Triassic sandstone, of the Black Forest and Odenwald. Only in one place the Gäue borders directly on the Rhine Valley, where Stromberg and Heuchelberg are located. The Stromberg lies between Pforzheim and Heilbronn and consists of three ridges. The Heuchelberg is a ridge about 15 kilometres long to the west of Heilbronn. Heuchelberg and Stromberg together form the Stromberg-Heuchelberg Nature Park. It was founded in 1980 and is the third nature park in Baden-Württemberg.

It is characterized by the escarpment of reed sandstone, behind which lie smaller plateaus and hilly landscapes. The plateaus are Keuper islands in a loess environment. The incision of the Enz valley exposes the layers of the lower Muschelkalk. The limestone layers in the area are karstified, but without any major caves. There are numerous karst springs and smaller, often water-bearing or intermittent caves. The plateaus often have deeper karstification, although the surface layers are not karstified. In this situation, the formation of collapse dolines is widespread.