Caverns

A cave is a hollow place in the ground, specifically a natural underground space large enough for a human to enter. Caves form naturally by the weathering of rock and often extend deep underground. The word cave can also refer to much smaller openings such as sea caves, rock shelters, and grottos. A cavern is a specific type of cave, naturally formed in soluble rock with the ability to grow speleothems.

Speleology is the science of exploration and study of all aspects of caves and the cave environment. Visiting or exploring caves for recreation may be called caving, potholing, or spelunking.

The formation and development of caves is known as speleogenesis, which can occur over the course of millions of years. Caves are formed by various geologic processes and can be variable sizes. These may involve a combination of chemical processes, erosion from water, tectonic forces, microorganisms, pressure, and atmospheric influences. Isotopic dating techniques can be applied to cave sediments, in order to determine the timescale when geologic events may have occurred to help form and shape present day caves.

It is estimated that the maximum depth of a cave cannot be more than 3,000 metres (9,800 ft) due to the pressure of overlying rocks. For karst caves the maximum depth is determined on the basis of the lower limit of karst forming processes, coinciding with the base of the soluble carbonate rocks.

Most caves are formed in limestone by dissolution.

Solutional caves or karst caves are the most frequently occurring caves and such caves form in rock that is soluble. Most occur in limestone, but they can also form in other rocks including chalk, dolomite, marble, salt, and gypsum. Rock is dissolved by natural acid in groundwater that seeps through bedding planes, faults, joints, and comparable features. Over geological epochs cracks expand to become caves and cave systems.

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