Before people started to build their own shelters, they lived in caves. Caves provided protection from animals and bad weather in winter, but also from other, hostile tribes. Caves are natural cavities in the Earth’s crust, which are most commonly formed on the rocky sides of the hills and cliffs. The science that studies caves is called Speleology.
Caves can also be defined as long and often branched underground, horizontal or slightly inclined channels that extend deep into the interior of the limestone masses. There are also examples of caves with steep channels. They were created in different ways. Some of them were created due to the constant impact of sea waves on the wall. Others emerged beneath the surface of the earth as old underground river basins, which had extruded the wall of the rock. There are also those caused by volcanic rocking or lava eruption.
Types of caves
The most common types of caves are those found in places where there are large limestone deposits. Under the influence of carbon dioxide-containing water, as well as other factors of nature, cavities that are formed will increase over time. Each drop of water falling from the ceiling of the cave contains little lime or some other mineral. Part of that water evaporates, but some of the mineral matter remains. In this way, cave decorations are created that hang from the ceiling – stalactites. From the stalactite drops water to the floor, so that the columns are formed, ie, stalagmites.
Caves consisting of one channel are called free, while those with multiple channels have a cavity spanning. The cave system consists of several channels at different levels of a cave. The main parts of the cave are the entrance, the channel (elongated cave hollow) and the cave hall. A spatial cavity is most often caused by the expansion of the cave channels. Some caves have a hole at the top. They opened up where the surface water was collected, and then pierced the path through the rock. Caves that do not have a surface connection are called caverns.
They can be dry, but often a river or stream flows through them. It happens that after the formation of the cave, the stream that flows through it find another stream so they move on as one. River caves are, in morphological and hydrographic terms, the most important forms in the interior of limestone masses. Through them, complicated systems of underground canals, run real “Cave Rivers”. In a large number of cases, these rivers are scattered like surface underground streams. Cave rivers can flow freely gravitational – under the action of Earth’s gravity, or ascendant – under the influence of hydrostatic pressure.