A cave or cavern is a hollow or empty space, inside the ground, formed naturally. It is a large place found underground where humans can also enter easily. Mostly, caves get formed as a result of the processes known as water erosion and weathering of rocks. When water passes through the large rocks, it takes along component parts of the rocks, giving birth to natural cavities called as caves. There are many factors like geologic, topographic and hydrologic which are responsible for the occurrence of caves. The formation, structure and shape of the caves are dependent on these factors. Some caves are also an outcome of volcanoes and earthquakes. The process of formation of caves can take thousands of years. The study of formation and development of caves is called speleogenesis.
Here are some amazing facts about caves:
- Solution caves are the most commonly found caves. They are the result of weathering of, mostly, limestone rocks, caused by acidic rainwater and groundwater while flowing through them. Most caves form in karst which is made up of limestone, dolomite and gypsum rocks easily dissoluble in acidic rainwater.
- Lava caves come into existence after a volcanic activity. They are, generally, very long. The outer surface of the lava flow cools off and solidifies but it flows out completely under the surface, forming a hollow tube, called as lava cave.
- Sea caves are formed when waves from the sea hit against weaker sea cliffs, rocky coastline or coral reefs, eroding away the soil and rock.
- Caves get formed in the glaciers and ice-bergs also. The melting ice creates a passage of water through the glacier. These are ice caves.
- One can find caves in the desert, called as wind caves, and formed by wind-blown sand rubbing off the cliff face of a sandstone cliff.
- As there is a pressure from overlying rocks, the maximum depth of a cave cannot exceed 3000 metres (9800 feet).
- Caves provide shelter to many animals and insects such as bears, wolves, bugs, bats, dung-beetles, grasshoppers, spiders and worms. They are also used by many mammals during hibernation in winter season.
- There are icicle-shaped rock formations emerging from the roof of the caves as water drips from it, called as stalactites. Some formations grow up from the floor like mushrooms which are called stalagmites and those which cover the walls of the cave like a waterfall are called flowstones. All of these rock formations are together known as speleothems.
- The three longest known cave systems in the world are: Mammoth Cave, Kentucky, USA, 6651.8 km (450 miles), Sistema Sac Actun/Sistema Dos Ojos, Mexico, 319 km (198.2 miles) and Jewel Cave, South Dakota, USA, 267.6 KM (166.3 miles).
- The deepest cave found on Earth is Voronya Cave in Georgia, at 2,197 metres (7,208 feet).
- The longest lava tube in the world is Kazuma Cave found near Hilo and is 66 kilometres or (41 miles) in length.
- Caves have been used to preserve the history of humans as we have discovered many archaeological treasures and ancient paintings in the caves across the world.
- A unique animal, called as Troglobites, is only adapted to the cave environment. They have unusual characteristics such as loss of pigment or colouring and loss of eyes due to extreme dark conditions in the cave.
- The longest cave found underwater is Systema Ox Bel Ha in Mexico which is 242 kilometres (150 miles) in length.
- The largest cave passage in the world is found in Vietnam, named as Son Doong Cave. It is 90 metres wide, 100 metres high and 2 kilometres long.