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. It has also been documented for more weathering-resistant rocks, such as quartzite, given the right conditions.
Hạ Long Bay or Halong Bay is a UNESCO World Heritage Site and popular travel destination in Quảng Ninh province, Vietnam. The name Hạ Long means "descending dragon". Administratively, the bay belongs to Hạ Long city, Cẩm Phả city, and is a part of Vân Đồn district. The bay features thousands of limestone karsts and islets in various shapes and sizes. Hạ Long Bay is a center of a larger zone that includes Bai Tu Long Bay to the northeast, and Cát Bà Island to the southwest. These larger zones share a similar geological, geographical, geomorphological, climate, and cultural characters.
Oshikoto is one of the fourteen regions of Namibia, named after Lake Otjikoto. Its capital is Omuthiya. The city of Tsumeb, Otjikoto's capital until 2008, and the towns of Omuthiya and Oniipa are also situated in this region. As of 2020, Oshikoto had 112,170 registered voters.
Tsumeb is a city of 15,000 inhabitants and the largest town in the Oshikoto region in northern Namibia. Tsumeb is known as the "gateway to the north" of Namibia. It is the closest town to the Etosha National Park. Tsumeb used to be the regional capital of Oshikoto until 2008 when Omuthiya was proclaimed a town and the new capital. The area around Tsumeb forms its own electoral constituency and has a population of 44,113. The town is the site of a deep mine that in its heyday was known as "TCL", but has since been renamed the Ongopolo Mine.
The Jenolan Caves are limestone caves located within the Jenolan Karst Conservation Reserve in the Central Tablelands region, west of the Blue Mountains, in Jenolan, Oberon Council, New South Wales, in eastern Australia. The caves and 3,083-hectare (7,620-acre) reserve are situated approximately 175 kilometres (109 mi) west of Sydney, 20 kilometres (12 mi) east of Oberon and 30 kilometres (19 mi) west of Katoomba. Dating back to 340million years ago, it is the oldest known and dated open cave system in the world.
Cross Cave, also named Cold Cave under Cross Mountain, is a cave in Slovenia's Lož Valley, in the area between the Lož Karst Field, Cerknica Karst Field, and Bloke Plateau. The cave is named after nearby Holy Cross Church in Podlož. The cave is particularly noted among Karst caves for its chain of over 45 subterranean lakes of emerald green water. Extremely slow-growing calcareous formations and their fragility are the main obstacle to large-scale tourism in the cave and limit daily tourist visits to the flooded part of the cave to four people. As a result, the Cross Cave is among the best-preserved caves, opened to the public in Slovenia. The cave was prepared for visits in the 1950s by the Lož Valley Tourist Association. It was later managed by the Ljubljana Cave Research Society. Since the 1990s, it has been cared for by the Friends of Cross Cave Association . With 45 species of organisms, some not discovered until 2000, Cross Cave is the fourth-largest cave ecosystem in the world in terms of biodiversity. The cave was first documented in 1832, but the part of the cave that includes lakes and stream passages was first explored by Slovene cavers in 1926.
Tilapia is a genus of cichlid fishes endemic to freshwater habitats in Southern Africa. In the past this was a very large genus including all species with the common name tilapia, but today the vast majority are placed in other genera.
The Otjikoto tilapia is a critically endangered species of cichlid fish endemic to Namibia where it was originally only found in Lake Guinas. This very small sinkhole lake contains quite clear water that generally ranges between 18–25 °C (64–77 °F) depending on season, and the Otjikoto tilapia has been seen down to depths of 67 m (220 ft). Despite deriving its common name from the nearby Lake Otjikoto, it in not native to that lake, rather being an introduced species. It is rare in the aquarium trade and also kept in garden ponds in southern Africa.
An underground lake or subterranean lake is a lake underneath the surface of the Earth. Most naturally occurring underground lakes are found in areas of karst topography, where limestone or other soluble rock has been weathered away, leaving a cave where water can flow and accumulate.
Otjikoto Lake is the smaller of only two permanent natural lakes in Namibia. It is a sinkhole lake that was created by a collapsing karst cave. It is located 20 kilometres (12 mi) north-west of Tsumeb and only 100 meters from the main road B1. The lake was declared a national monument in 1972.
Guinas Constituency is an electoral constituency in the Oshikoto Region of Namibia. It had 8,435 inhabitants in 2004 and 4,210 registered voters in 2020. Guinas consists of the rural area surrounding the mining town of Tsumeb. Larger settlements in the Guinas constituency are Oshivelo and Tsintsabis.
Namibia, a country in south-western Africa, has a total of 124 known caves, 41 of which are situated in the Otjozondjupa Region.
The Baradla Domica cave system is a large cave system in northern Hungary. As part of the Aggtelek Karst, it extends more than 25.5 km (25,500 m) and includes the 5.3 km (3.3 mi) Domica cave. A significant part of the cave has varied colors and shapes providing an unparalleled spectacle of decorative stalactites.
The Račna Karst Field is a karst field in the northern edge of the Lower Carniolan karst area, south of Grosuplje, Slovenia. It has rich natural and cultural value. Because of its ecological significance, it is anticipated that a nature park will be established there and that it will be included in the Natura 2000 program.
Krka Cave is a horizontal karst cave and an occasional source of the Krka River in Dry Carniola, central Slovenia. It lies in a pocket valley between the villages of Trebnja Gorica to the east and Gradiček to the west, north of the village of Krka. Water flows into the cave from the Račna Karst Field south of the town of Grosuplje and emerges a few metres below the cave's main entrance in the karst spring of the Krka. The cave, which is of archaeological and historical significance and features great fauna diversity, is open to announced tourist visits in the presence of a guide and also used as an event venue.
Karst lakes are formed as the result of a collapse of caves, especially in water-soluble rocks such as limestone, gypsum and dolomite. This process is known as karstification. They can cover areas of several hundred square kilometres. Their shallow lakebed is usually an insoluble layer of sediment so that water is impounded, leading to the formation of lakes. Many karst lakes only exist periodically, but return regularly after heavy rainfall.
Wonderfonteinspruit is a small river situated in the Highveld region of South Africa. Its source has been disputed in the past, although it is now accepted that the river originates in the West Rand of Gauteng between Krugersdorp and Randfontein, at the Tudor Dam, which was initially used as a storage dam for the Luiperdsvlei Gold Plant. In the past the river received a majority of its water from karst springs along its course. The river flows through one of the richest gold-producing areas in the world, which led to the dolomitic compartments which fed the river being dewatered to make way for mining activities. This led to the drying up of the karst springs that fed the river.
Guajataca State Forest is one of the 20 forests that make up the public forest system of Puerto Rico. The Guajataca Forest is located in the northwestern part of Puerto Rico, along the Northern Karst zone in the municipality of Isabela and municipality of Quebradillas, and is near Camuy and San Sebastián. The forest is renowned for its ecological diversity, the mogotes and karstic formations, and its numerous caves and canyons. It also has the largest trail system of any Puerto Rican state forest.
