A cave or cavern is a natural void in the ground, specifically a space large enough for a human to enter. Caves often form by the weathering of rock and often extend deep underground. The word cave can refer to smaller openings such as sea caves, rock shelters, and grottos, that extend a relatively short distance into the rock and they are called exogene caves. Caves which extend further underground than the opening is wide are called endogene caves.
Karst is a topography formed from the dissolution of soluble carbonate rocks such as limestone, dolomite, and gypsum. It is characterized by features like poljes above and drainage systems with sinkholes and caves underground. More weathering-resistant rocks, such as quartzite, can also occur, given the right conditions.
Wookey Hole Caves are a series of limestone caverns, a show cave and tourist attraction in the village of Wookey Hole on the southern edge of the Mendip Hills near Wells in Somerset, England. The River Axe flows through the cave. It is a Site of Special Scientific Interest (SSSI) for both biological and geological reasons. Wookey Hole cave is a "solutional cave", one that is formed by a process of weathering in which the natural acid in groundwater dissolves the rocks. Some water originates as rain that flows into streams on impervious rocks on the plateau before sinking at the limestone boundary into cave systems such as Swildon's Hole, Eastwater Cavern and St Cuthbert's Swallet; the rest is rain that percolates directly through the limestone. The temperature in the caves is a constant 11 °C (52 °F).
A sinkhole is a depression or hole in the ground caused by some form of collapse of the surface layer. The term is sometimes used to refer to doline, enclosed depressions that are also known as shakeholes, and to openings where surface water enters into underground passages known as ponor, swallow hole or swallet. A cenote is a type of sinkhole that exposes groundwater underneath. Sink and stream sink are more general terms for sites that drain surface water, possibly by infiltration into sediment or crumbled rock.
The Vercors massif are a range in France consisting of rugged plateaus and mountains straddling the départements of Isère and Drôme in the French Prealps. It lies west of the Dauphiné Alps, from which it is separated by the rivers Drac and Isère. The cliffs at the massif's eastern limit face the city of Grenoble.
The Li River or Li Jiang is the name for the upper reaches of the Gui River in northeastern Guangxi, China. It is part of the Xijiang River system in the Pearl River basin, flowing 164 kilometres (102 mi) from Xing'an County to Pingle County.
Flynn Creek crater is an impact crater situated in Jackson County, Tennessee, approximately 8 km south of Gainesboro.
The Gunung Mulu National Park is a national park in Miri Division, Sarawak, Malaysia. It is a UNESCO World Heritage Site that encompasses caves and karst formations in a mountainous equatorial rainforest setting. The park is famous for its caves and the expeditions that have been mounted to explore them and their surrounding rainforest, most notably the Royal Geographical Society Expedition of 1977–1978, which saw over 100 scientists in the field for 15 months. This initiated a series of over 20 expeditions now named the Mulu Caves Project.
The Delaware Basin is a geologic depositional and structural basin in West Texas and southern New Mexico, famous for holding large oil fields and for a fossilized reef exposed at the surface. Guadalupe Mountains National Park and Carlsbad Caverns National Park protect part of the basin. It is part of the larger Permian Basin, itself contained within the Mid-Continent oil province.
Sarawak Chamber is the largest known cave chamber in the world by area and the second largest by volume after the Miao Room in China. It is in Gua Nasib Bagus, which is located in Gunung Mulu National Park in the Malaysian territory of Sarawak on the island of Borneo.
The Jeita Grotto is a system of two separate, but interconnected, karstic limestone caves spanning an overall length of nearly 9 kilometres (5.6 mi). The caves are situated in the Nahr al-Kalb river valley within the locality of Jeita, 18 kilometres (11 mi) north of the Lebanese capital Beirut. Though inhabited in prehistoric times, the lower cave was not rediscovered until 1836 by Reverend William Thomson; it can only be visited by boat since it channels an underground river that provides fresh drinking water to more than a million Lebanese.
The Marble Arch Caves are a series of natural limestone caves located near the village of Florencecourt in County Fermanagh, Northern Ireland. The caves are named after the nearby Marble Arch, a natural limestone arch at the upstream end of Cladagh Glen under which the Cladagh River flows. The caves are formed from three rivers draining off the northern slopes of Cuilcagh mountain, which combine underground to form the Cladagh. On the surface, the river emerges from the largest karst resurgence in Ireland, and one of the largest in the United Kingdom. At 11.5 kilometres (7.1 mi) the Marble Arch Caves form the longest known cave system in Northern Ireland, and the karst is considered to be among the finest in the British Isles.
A blue hole is a large marine cavern or sinkhole, which is open to the surface and has developed in a bank or island composed of a carbonate bedrock. Blue holes typically contain tidally influenced water of fresh, marine, or mixed chemistry. They extend below sea level for most of their depth and may provide access to submerged cave passages. Well-known examples are the Dragon Hole and, in the Caribbean, the Great Blue Hole and Dean's Blue Hole.
Deer Cave, located near Miri, Sarawak, Malaysia, is a show cave attraction of Gunung Mulu National Park. It was surveyed in 1961 by G. E. Wilford of the British Borneo Geological Survey, who predicted that Mulu would yield many more caves in the future. The cave, which is also known as Gua Payau or Gua Rusa by the local Penan and Berawan people, is said to have received its name because of the deer that go there to lick salt-bearing rocks and shelter themselves.
Fengshan County is a county of Guangxi, China. It is under the administration of Hechi City.
The Danxia landform refers to various landscapes found in southeast, southwest and northwest China that "consist of a red bed characterized by steep cliffs". It is a unique type of petrographic geomorphology found in China. Danxia landform is formed from red-coloured sandstones and conglomerates of largely Cretaceous age. The landforms look very much like karst topography that forms in areas underlain by limestones, but since the rocks that form danxia are sandstones and conglomerates, they have been called "pseudo-karst" landforms. They were formed by endogenous forces and exogenous forces.
Anou Boussouil is a limestone karst cave located in the mountains of Djurdjura, Algeria. The cave is 3,200 metres (10,500 ft) long and 805 metres (2,641 ft) deep. The entrance to the cave is 1,074 metres (3,524 ft) up the mountainside. During the springtime rainy season, melting snow pours through a channel leading directly to the cave mouth, continuing the process of erosion. This distinguishes it from other caves in the Djurdjura range, which are inactive and no longer being enlarged through erosion.
The Pancake Rocks and Blowholes are a coastal rock formation at Punakaiki on the West Coast of the South Island of New Zealand. They are a popular visitor attraction.
Cave diving is underwater diving in water-filled caves. The equipment used varies depending on the circumstances, and ranges from breath hold to surface supplied, but almost all cave diving is done using scuba equipment, often in specialised configurations with redundancies such as sidemount or backmounted twinset. Recreational cave diving is generally considered to be a type of technical diving due to the lack of a free surface during large parts of the dive, and often involves planned decompression stops. A distinction is made by recreational diver training agencies between cave diving and cavern diving, where cavern diving is deemed to be diving in those parts of a cave where the exit to open water can be seen by natural light. An arbitrary distance limit to the open water surface may also be specified. Despite the risks, water-filled caves attract scuba divers, cavers, and speleologists due to their often unexplored nature, and present divers with a technical diving challenge.
