Gypsum Caves

Gypsum Karst

the lake, which mirrors the sheets of the tannery was made artificially to protect this sheets. ShowcaveBarbarossahöhle in RegionGermany.

Gypsum karst is very rare. It depends on deposits of gypsum or anhydrite, often also called alabaster. Chemically it is calcium sulfate CaSO4.

Gypsum is much rarer than limestone, as it needs very special conditions:

  1. You need a depression, in which sea water is trapped and evaporated to form gypsum deposits.
  2. It has to be an arid part of the world.
    Gypsum is deposited when sea water is evaporated by the sun and the concentration of numerous salts in the water grows. Rain would revert this process and solute the gypsum.
  3. With temporary connection to the sea.
    There must be a continuous or periodical (sea) water afflux, to allow the deposit of a decent amount of gypsum. If there is no (temporary) connection to the sea, the layer would be rather thin.

Now you have gypsum, but there is another problem: water is able to solute gypsum without the complicated CO2 stuff with limestone. And it will do it much faster and be able to solute a much higher amount!

For gypsum karst this means:

  1. It is very rare!
  2. It is always very young! Getting older means to disappear.
  3. The caves are often very big!

The longest gypsum cave of the world is Optimisticheskaya Cave in Ukraine with 165 km of passage. Because of their size, numerous gypsum caves are used as show caves.