Instruct: Given a question, retrieve relevant passages that answer the question.
Query: What is the deepest point in the Caspian Sea?
Differences between the three regions are dramatic. The Northern Caspian only includes the Caspian shelf, and is very shallow; it accounts for less than 1% of the total water volume with an average depth of only . The sea noticeably drops off towards the Middle Caspian, where the average depth is . The Southern Caspian is the deepest, with oceanic depths of over , greatly exceeding the depth of other regional seas, such as the Persian Gulf. The Middle and Southern Caspian account for 33% and 66% of the total water volume, respectively. The northern portion of the Caspian Sea typically freezes in the winter, and in the coldest winters ice forms in the south as well.
The lake is deep at its deepest point, which makes it the deepest lake in the United States, the second-deepest in North America and the ninth-deepest in the world. Crater Lake is often referred to as the seventh-deepest lake in the world, but this former listing excludes the approximately depth of subglacial Lake Vostok in Antarctica, which resides under nearly of ice, and the recent report of a maximum depth for Lake O'Higgins/San Martin, located on the border of Chile and Argentina. However, when comparing its average depth of to the average depth of other deep lakes, Crater Lake becomes the deepest in the Western Hemisphere and the third-deepest in the world. The impressive average depth of this volcanic lake is due to the nearly symmetrical caldera formed 7,700 years ago during the violent climactic eruptions and subsequent collapse of Mount Mazama and the relatively moist climate that is typical of the crest of the Cascade Range.
In 2005, Hawkes and adventurer Steve Fossett teamed up to create a submarine that could be piloted by an individual to the deepest part of the ocean. This spot in the Pacific Ocean, called Challenger Deep, is approximately under the ocean's surface and is thought to be the deepest point in the ocean. Together they began to develop the "Challenger" submersible with this goal in mind. However, in 2007 Fossett lost his life in a fatal accident in the Sierra Nevada Mountains of California before the feat could be attempted.
, negotiations related to the demarcation of the Caspian Sea had been going on for nearly a decade among the states bordering the Caspian – Azerbaijan, Russia, Kazakhstan, Turkmenistan, and Iran. The status of the Caspian Sea is the key problem. Access to mineral resources (oil and natural gas), access for fishing, and access to international waters (through Russia's Volga river and the canals connecting it to the Black Sea and Baltic Sea) all depend upon the outcomes of negotiations. Access to the Volga River is particularly important for the landlocked states of Azerbaijan, Kazakhstan, and Turkmenistan. This concerns Russia, because the potential traffic would use its inland waterways. If a body of water is labelled as a sea, then there would be some precedents and international treaties obliging the granting of access permits to foreign vessels. If a body of water is labelled merely as a lake, then there are no such obligations. Environmental issues are also somewhat connected to the status and borders issue.
Baku, which is the starting point of all sea routes of Azerbaijan, is the largest port of the Caspian Sea. Azerbaijan has access to the oceans along the Caspian Sea-Volga-Volga-Don Canal, and the Don-Sea of Azov. Along with the Volga-Don Canal, the Azerbaijani vessels have the opportunity to enter the world ocean through the Volga-Baltic and White Sea-Baltic canals. Moreover, oil tankers are being transported through the Caspian Sea. Baku Sea Trade Port and Caspian Shipping Company CJSC, have a big role in the sea transportation of Azerbaijan. The Caspian Sea Shipping Company CJSC, along with the transport fleet, also includes a specialized fleet and shipyards. The transport fleet consists of 51 vessels, including 20 tankers, 13 ferries, 15 universal dry cargo vessels, 2 Ro-Ro vessels, as well as 1 technical vessel and 1 floating workshop. The specialized fleet includes 210 vessels, including 20 cranes, 25 towing and supplying vehicles, 26 passenger, two pipe-laying, six fire-fighting, seven engineering-geological, two diving and 88 auxiliary vessels.
The Mariana Trench or Marianas Trench is located in the western Pacific Ocean approximately east of the Mariana Islands, and has the deepest natural trench in the world. It is a crescent-shaped trough in the Earth's crust averaging about long and wide. The maximum known depth is (± ) at the southern end of a small slot-shaped valley in its floor known as the Challenger Deep. However, some unrepeated measurements place the deepest portion at . For comparison: if Mount Everest were dropped into the trench at this point, its peak would still be over under water.
The difference in elevation of the cave's entrance and its deepest explored point is . It became the deepest-known cave in the world in 2001 when the expedition of the Ukrainian Speleological Association reached a depth of which exceeded the depth of the previous deepest-known cave, Lamprechtsofen, in the Austrian Alps, by . In 2004, for the first time in the history of speleology, the Ukrainian Speleological Association expedition reached a depth greater than , and explored the cave to . Ukrainian diver Gennadiy Samokhin extended the cave by diving in the terminal sump to 46 metres' depth in 2007 and then to 52 m in 2012, setting successive world records of 2,191 m and 2,197 m, respectively. Krubera is one of the two known caves on Earth deeper than 2,000 metres.
Archeological studies of Gobustan petroglyphs indicate that there once had been dolphins and porpoises, or a certain species of beaked whales and a whaling scene indicates large baleen whales likely being present in Caspian Sea at least until when the Caspian Sea ceased being a part of the ocean system or until the Quaternary or much more recent periods such as until the last glacial period or antiquity. Although the rock art on Kichikdash Mountain is assumed to be of a dolphin or of a beaked whale, it might instead represent the famous beluga sturgeon due to its size (430 cm in length), but fossil records suggest certain ancestors of modern dolphins and whales, such as "Macrokentriodon morani" (bottlenose dolphins) and "Balaenoptera sibbaldina" (blue whales) were presumably larger than their present descendants. From the same artworks, auks, like Brunnich's Guillemot could also have been in the sea as well, and these petroglyphs suggest marine inflow between the current Caspian Sea and the Arctic Ocean or North Sea, or the Black Sea. This is supported by the existences of current endemic, oceanic species such as lagoon cockles which was genetically identified to originate in Caspian/Black Seas regions.
The species is distributed throughout brackish and fresh waters of the Ponto-Caspian basin. It is found in the Caspian Sea, the Sea of Azov, rivers Volga, Don, Kuban and Danube; in the rivers up to over 500 km upstream. All the previous mentionings of "P. baeri" outside the Caspian Sea should probably be attributed to "P. bakuensis". The ranges of "P. bakuensis" and "P. baeri" partly overlap: they can be found together in the Caspian Sea.
Neogobius pallasi, the Caspian sand goby or the Caspian monkey goby, is a species of fish native to fresh and brackish waters of the Caspian Sea basin including the Volga drainage up to the vicinity of Moscow. It has been introduced into the Aral basin. This species of goby can reach a length of SL. It is also important to local commercial fisheries.
The cave is the deepest known cave in Asia having been explored to a depth of from the entrance. At the lowest discovered level a water-filled siphon blocks further exploration. It is thought that the cave has the potential to be the deepest known cave in the world, with a theorised depth of making it deeper than the Veryovkina Cave. The explored length of the cave is .
Jujar is deepest cave of Asia. in 7 September 2015 Jujar cave in eastern front of the Paraw recognized as deepest cave of Iran. an Iranian caving team consist of 24 athlete has discovered 806 meter and 8 centimeter of this cave. before this event Paraw cave (also located in this mount ) was deepest cave of Iran. in August 2016 an international expedition started to discover whole of the cave. eventually they announced that they successfully achieved to more than 1000 meter depth of the cave. thus Jujar became deepest cave of Asia and Iran.
Trieste is a Swiss-designed, Italian-built deep-diving research bathyscaphe, which with its crew of two reached a record maximum depth of about , in the deepest known part of the Earth's oceans, the Challenger Deep, in the Mariana Trench near Guam in the Pacific. On 23 January 1960, Jacques Piccard (son of the boat's designer Auguste Piccard) and US Navy Lieutenant Don Walsh achieved the goal of Project Nekton.
Balkhash lies in the deepest part of the vast Balkhash-Alakol depression, which was formed by a sloping trough between mountains of the Alpine orogeny and the older Kazakhstan Block during the Neogene and Quaternary. Rapid erosion of the Tian Shan has meant the depression subsequently filled with sand river sediments in what is geologically a very short time span. The basin is a part of Dzungarian Alatau, which also contains lakes Sasykkol, Alakol and Aibi. These lakes are remnants of an ancient sea which once covered the entire Balkhash-Alakol depression, but was not connected with the Aral–Caspian Depression.
The Convention grants jurisdiction over 15 miles of territorial waters to each neighboring country, plus additional 10 miles of exclusive fishing rights on the surface, while the rest is international waters. The seabed, on the other hand, remains undefined, subject to bilateral agreements between countries. Thus, the Caspian Sea is legally neither fully a sea nor a lake.
Pascal Bernabé is a French scuba diver who in 2005 laid claim to the world best for depth on a deep dive using self-contained breathing apparatus. Bernabé claimed to have reached a maximum depth of using trimix on 5 June 2005 near Propriano, Corsica. This was actually deeper than the official deepest scuba dive recognized by Guinness World Records at the time. That mark, set by Nuno Gomes in Dahab, Egypt, was of sea water. However, Bernabé's claimed deepest dive was not included in the "Guinness Book of World Records" due to insufficient evidence of such a dive ever being performed.
Chevé Cave ( ; ) is a deep cave located in the Sierra Juárez mountain range in the southern Mexico state of Oaxaca. As of 2003, its deepest point has been measured at deep, making it the second deepest known cavern in the Western Hemisphere and the world’s 12th deepest cave. The cave's deepest known point is nearly one vertical mile and seven horizontal miles from the entrance, ending in a terminal sump. The present limit of exploration in Chevé, at 9.3 kilometers from the nearest entrance, represents one of the most remote locations ever attained inside any cave on Earth. The logistics of reaching this point are enormous: more than two kilometers of rope need to be rigged and three underground camps established. Chevé is the deepest proven freshwater hydrological system in the world. Temperatures in Chevé are moderate, ranging from . It has been most thoroughly explored under the leadership of caver Bill Stone.
The Caspians ( "Kaspioi", Aramaic: "kspy", "kaspielebiʿ", "kaspkʿ", "Kāspiān") were a people of antiquity who dwelled along the southern and southwestern shores of the Caspian Sea, in the region known as Caspiane. "Caspian" is the English version of the Greek ethnonym "Kaspioi", mentioned twice by Herodotus among the Achaemenid satrapies of Darius and applied by Strabo. The name is not attested in Old Iranian.
Turkic languages refer to the lake as "Khazar Sea". In Turkmen, the name is , in Azeri, it is , and in modern Turkish, it is . In all these cases, the second word simply means "sea", and the first word refers to the historical Khazars who had a large empire based to the north of the Caspian Sea between the 7th and 10th centuries. An exception is Kazakh, where it is called , "Kaspiy teñizi" (Caspian Sea).
Many of the world's largest lakes are located in rift valleys. Lake Baikal in Siberia, a World Heritage Site, lies in an active rift valley. Baikal is both the deepest lake in the world and, with 20% of all of the liquid freshwater on earth, has the greatest volume. Lake Tanganyika, second by both measures, is in the "Albertine Rift", the westernmost arm of the active East African Rift. Lake Superior in North America, the largest freshwater lake by area, lies in the ancient and dormant Midcontinent Rift. The largest subglacial lake, Lake Vostok, may also lie in an ancient rift valley. Lake Nipissing and Lake Timiskaming in Ontario and Quebec, Canada lie inside a rift valley called the Ottawa-Bonnechere Graben. Þingvallavatn, Iceland's largest natural lake, is also an example of a rift lake.
The Yap Trench is an oceanic trench near Yap Island in the western Pacific Ocean. The trench forms the part of the Pacific Ring of Fire between the Palau Islands and the Mariana Trench. It is 650 kilometres (400 mi) long and 8,527 metres (27,976 ft) deep at its deepest point.
The Caspian has characteristics common to both seas and lakes. It is often listed as the world's largest lake, although it is not a freshwater lake. It contains about 3.5 times more water, by volume, than all five of North America's Great Lakes combined. The Caspian was once part of the Tethys Ocean, but became landlocked about 5.5 million years ago due to plate tectonics. The Volga River (about 80% of the inflow) and the Ural River discharge into the Caspian Sea, but it has no natural outflow other than by evaporation. Thus the Caspian ecosystem is a closed basin, with its own sea level history that is independent of the eustatic level of the world's oceans.
Geologically, the Caspian Sea, like the Black and Mediterranean seas, is a remnant of the ancient Tethys Ocean. The deepest area is oceanic rather than continental crust. However, it is generally regarded by geographers as a large endorheic salt lake.
The Caspian Sea, like the Black Sea, Namak Lake, and Lake Urmia, is a remnant of the ancient Paratethys Sea. It became landlocked about 5.5 million years ago due to tectonic uplift and a fall in sea level. During warm and dry climatic periods, the landlocked sea almost dried up, depositing evaporitic sediments like halite that were covered by wind-blown deposits and were sealed off as an evaporite sink when cool, wet climates refilled the basin. (Comparable evaporite beds underlie the Mediterranean.) Due to the current inflow of fresh water, the Caspian Sea is a freshwater lake in its northern portions, and is most saline on the Iranian shore, where the catchment basin contributes little flow. Currently, the mean salinity of the Caspian is one third that of Earth's oceans. The Garabogazköl embayment, which dried up when water flow from the main body of the Caspian was blocked in the 1980s but has since been restored, routinely exceeds oceanic salinity by a factor of 10.
The Black Sea-Caspian Steppe is an informal name for that part of the Eurasian Steppe that extends south between the Black and Caspian Seas. It is usually treated as part of the Pontic-Caspian steppe which includes the area north of the Black and Caspian Seas, but there is some reason to treat it as a distinct place. Its natural boundaries are the Sea of Azov and Black Sea on the west, the Caucasus Mountains on the south and the Caspian Sea on the east. Its northern boundary may be taken as the triangle formed by the lower Don River and Volga River which are about 60 km apart to the west of Volgograd. This article excludes the north slope of the Caucasus which is not steppe and has a distinct geography and history.