Caves and Karst

Unlike mines, tunnels, or basements, caves are formed naturally, that is, without human intervention. They are large enough for a person to move around inside. This does not mean that a cave is always easy to navigate. Often, movement is only possible by crawling or using single-rope techniques. Caves can occur in almost all types of solid rock and in ice. If the cavities formed at the same time as the surrounding rock, they are called primary caves. These include, among others, volcanic rock caves such as underground lava tunnels or gas bubbles.

Most caves, however, form after the rock has solidified as secondary caves through weathering processes such as erosion, dissolution, or through movement processes such as slope failures or rockfalls. Dissolution caves represent the most significant type of cave worldwide. These caves develop in limestone, dolomite, gypsum, and salt rocks. Along rock joints, groundwater can initially form small tubes through dissolution, which then expand into caves. Caves formed by dissolution are called karst caves. The majority of caves are located in karst regions. In addition to caves, these areas often feature impressive surface landforms. Sinkholes (funnel-shaped depressions), sinkholes, disappearing streams, large springs, or sharply eroded rock surfaces—so-called karren fields—shape the landscape and give it a distinctive character.

Caves therefore frequently occur where water-soluble rocks make up a significant portion of the stratigraphic sequence. Karst regions are found throughout Germany, concentrated in the low mountain ranges and the Alps. They cover about 12% of the total area and to date, approximately 15,000 caves have been officially recorded in Germany.

They also serve as a significant habitat. In Germany alone, over 750 animal species depend on subterranean habitats. They hibernate, spend the summer, or complete their entire life cycle there. Bats are among the strictly protected species.
Caves are sites of paleontological and archaeological remains that date back to the very beginnings of humanity and beyond. Cave sediments and stalactites serve as geological climate archives.