Earth

Underground water

Water commonly found underground creating caves is mainly of meteoric origin, however other kinds of water may be mixed to it in various ways. The following can be found: “Connate” water, i.e. ancient water that was trapped in a sedimentary rock during its formation, and generally very rich in salts, and therefore potentially very aggressive; deep so-called "juvenile" water, produced by magma activity, often very hot and aggressive; or meteoric water that reaches the deeper layers where it is heated and enriched with salts and acids and then comes out at the surface again through faults, generally with the characteristics of hydrothermal water. These are almost always very aggressive waters and generally their temperature is high. When these deep waters come into contact with the rock, they give rise to very rapid and intense dissolution processes, known as hyperkarst processes creating particular caves, called hypogenic caves (i.e. generated from the deep) as for example the Grotta Giusti cave near Pistoia.