Optymistychna ( uk, Оптимістична: meaning "optimistic", also known as Peschtschera Optimistitscheskaya) is a

gypsum Gypsum is a soft sulfate mineral composed of calcium sulfate dihydrate, with the chemical formula . It is widely mined and is used as a fertilizer and as the main constituent in many forms of plaster, blackboard or sidewalk chalk, and drywa ...

cave 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 ...

located near the

Ukrainia Ukraine ( uk, Україна, Ukraïna, ) is a country in Eastern Europe. It is the second-largest European country after Russia, which it borders to the east and northeast. Ukraine covers approximately . Prior to the ongoing Russian inva ...

n village of Korolivka, Chortkiv Raion,

Ternopil Oblast Ternopil Oblast ( uk, Тернопі́льська о́бласть, translit=Ternopilska oblast; also referred to as Ternopilshchyna, uk, Терно́пільщина, label=none, or Ternopillia, uk, Тернопілля, label=none) is an obl ...

. Approximately of passageways have been mapped within. As a result, it is the longest cave in

Eurasia Eurasia (, ) is the largest continental area on Earth, comprising all of Europe and Asia. Primarily in the Northern and Eastern Hemispheres, it spans from the British Isles and the Iberian Peninsula in the west to the Japanese archipelag ...

and the fifth-longest cave in the world, after

Mammoth Cave Mammoth Cave National Park is an American national park in west-central Kentucky, encompassing portions of Mammoth Cave, the longest cave system known in the world. Since the 1972 unification of Mammoth Cave with the even-longer system under F ...

Sistema Sac Actun Sistema Sac Actun (from Spanish and Yucatec Maya meaning "White Cave System") is an underwater cave system situated along the Caribbean coast of the Yucatán Peninsula with passages to the north and west of the city of Tulum. Discovery of a connec ...

Jewel Cave Jewel Cave National Monument contains Jewel Cave, currently the third longest cave in the world, with of mapped passageways. It is located approximately west of the town of Custer in Black Hills of South Dakota. It became a national monument ...

and Sistema Ox Bel Ha. It is also the longest

cave in the world.

History

The cave complex was discovered by the speleologists of the Lviv speleological club "Cyclope" in 1966. It was entirely unknown before then. There have been more than 50 expeditions since then, but exploration has slowed significantly in recent years, and very little surveying is currently being done. The cave is located very close to the

Priest's Grotto Priest's Grotto (also known as ''Ozerna'' or ''Blue Lakes'' ua, Озерна, meaning: "lake") is a cave in western Ukraine near the village of Strilkivtsi ( ua, Стрілківці), located within Chortkiv Raion (District) of Ternopil Oblast ...

or Ozerna Cave, the eleventh-longest cave in the world at , but the two caves have not yet been found to be connected. In 2008, the cave was recognized as a Natural Wonder of Ukraine.

Geology

The entire cave lies under a 2 km square area in a layer of

Neogene period The Neogene ( ), informally Upper Tertiary or Late Tertiary, is a geologic period and system that spans 20.45 million years from the end of the Paleogene Period million years ago ( Mya) to the beginning of the present Quaternary Period Mya. ...

gypsum that is less than thick. The passages tend to be fairly small, no more than wide and tall for most, although at intersections they can be up to tall. They are often choked with mud. They comprise a dense network on several levels, making Optymistychna known as a "maze cave". Optymistychna's gypsum bed is topped with a limestone layer, which has seeped through into the cave via erosion and formed into

calcite Calcite is a carbonate mineral and the most stable polymorph of calcium carbonate (CaCO3). It is a very common mineral, particularly as a component of limestone. Calcite defines hardness 3 on the Mohs scale of mineral hardness, based on scratc ...

speleothem A speleothem (; ) is a geological formation by mineral deposits that accumulate over time in natural caves. Speleothems most commonly form in calcareous caves due to carbonate dissolution reactions. They can take a variety of forms, dependi ...

s. At other places, the gypsum has formed crystals, often tinted a multitude of colors by

mineral salt Halite (), commonly known as rock salt, is a type of salt, the mineral (natural) form of sodium chloride ( Na Cl). Halite forms isometric crystals. The mineral is typically colorless or white, but may also be light blue, dark blue, purple, pi ...

s. In some areas, large gypsum rosettes have formed, colored black by

Manganese oxide Manganese oxide is any of a variety of manganese oxides and hydroxides.Wells A.F. (1984) ''Structural inorganic chemistry'' 5th edition Oxford Science Publications, . These include * Manganese(II) oxide, MnO * Manganese(II,III) oxide, Mn3O4 * Man ...

Notes

References

External links

Official site of Optimistic cave

Chapter II.9, Gypsum Karst in the Western Ukraine by Alexander Klimchouk
article appearing in: International Journal of Speleology, vol. 25, #3-4, 1996, p. 263-278. {{DEFAULTSORT:Optymistychna Geography of Ternopil Oblast Gypsum caves Caves of Ukraine Natural heritage sites in Ternopil Oblast

History

Geology

Notes

See also

References

External links