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Anatakitaki Cave
Anatakitaki Cave, or the Cave of the Kopekas, is a karst cave located in the northeast of Atiu, Cook Islands. The cave is a large solutional cave, with many offshoot chambers and passages. A freshwater lake is to be found at the base of the cave. The Tiroto Tunnel connects this lake to the Pacific Ocean, and can be waded along until the last portion which is totally submerged. There is a great array of all sorts of speleothems decorating the cave throughout its length. The cave's alternate name comes from its population of Atiu swiftlet The Atiu swiftlet or Sawtell's Swiftlet (''Aerodramus sawtelli'') is a species of bird in the swift family, endemic to Atiu in the Cook Islands. This small, dark swift measures long. It is sooty-brown above, slightly lighter below. Its natural ...s, which roost in the cave in vast numbers. They never land outside of the cave, and use echolocation just like bats. Roots, mainly from banyan trees, permeate the cave to its furthest depths.htt ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Atiu
Atiu, also known as Enuamanu (meaning ''land of the birds''), is an island of the Cook Islands archipelago, lying in the central-southern Pacific Ocean. Part of the Nga-pu-Toru, it is northeast of Rarotonga. The island's population has dropped by two-thirds in the last 50 years. Geography Atiu is a raised volcanic island surrounded by a reef from which rise cliffs of fossilized coral (''makatea''). The makatea cliff forms a ring round the island, creating a virtual plateau. Erosion of the inside of the ring has formed a dip of about into fertile land, which gradually rises again to a central flat-topped hill. The low swampy land consists of taro plantations, marshes and a lake, Tiroto. This fertile area also grows bananas, citrus fruits, pawpaws, breadfruit and coconuts. The island is surrounded by a fringing reef. The ''makatea'' is honeycombed with caves, some of which have been used for burials. History Polynesians are believed to have lived on Atiu since at least ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Karst
Karst is a topography formed from the dissolution of soluble rocks such as limestone, dolomite, and gypsum. It is characterized by underground drainage systems with sinkholes and caves. It has also been documented for more weathering-resistant rocks, such as quartzite, given the right conditions. Subterranean drainage may limit surface water, with few to no rivers or lakes. However, in regions where the dissolved bedrock is covered (perhaps by debris) or confined by one or more superimposed non-soluble rock strata, distinctive karst features may occur only at subsurface levels and can be totally missing above ground. The study of ''paleokarst'' (buried karst in the stratigraphic column) is important in petroleum geology because as much as 50% of the world's hydrocarbon reserves are hosted in carbonate rock, and much of this is found in porous karst systems. Etymology The English word ''karst'' was borrowed from German in the late 19th century, which entered German much earlier ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cook Islands
) , image_map = Cook Islands on the globe (small islands magnified) (Polynesia centered).svg , capital = Avarua , coordinates = , largest_city = Avarua , official_languages = , languages_type = Spoken languages , languages = , ethnic_groups = , ethnic_groups_year = 2016 census , demonym = Cook Islander , government_type = , leader_title1 = Monarch , leader_name1 = , leader_title2 = 's Representative , leader_name2 = Sir Tom Marsters , leader_title3 = Prime Minister , leader_name3 = Mark Brown , leader_title4 = President of the House of Ariki , leader_name4 = Tou Travel Ariki , legislature = Parliament , sovereignty_type = Associated state of New Zealand , established_event1 = Self-governance , established_date1 = 4 August 1965 , establi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Solutional Cave
A solutional cave, solution cave, or karst cave is a cave usually formed in the soluble rock limestone. It is the most frequently occurring type of cave. It can also form in other rocks, including chalk, dolomite, marble, salt beds, and gypsum. Process Bedrock is dissolved by natural acid in groundwater that seeps through bedding-planes, faults, joints and so on. Over geological epochs these openings expand as the walls are dissolved to become caves or cave systems. The portions of a solutional cave that are below the water table or the local level of the groundwater will be flooded. Limestone caves The largest and most abundant solutional caves are located in limestone. Limestone caves are often adorned with calcium carbonate formations produced through slow precipitation. These include flowstones, stalactites, stalagmites, helictites, soda straws, calcite rafts and columns. These secondary mineral deposits in caves are called ''speleothems''. Carbonic acid dissoluti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pacific Ocean
The Pacific Ocean is the largest and deepest of Earth's five oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean (or, depending on definition, to Antarctica) in the south, and is bounded by the continents of Asia and Oceania in the west and the Americas in the east. At in area (as defined with a southern Antarctic border), this largest division of the World Ocean—and, in turn, the hydrosphere—covers about 46% of Earth's water surface and about 32% of its total surface area, larger than Earth's entire land area combined .Pacific Ocean . '' Britannica Concise.'' 2008: Encyclopædia Britannica, Inc. The centers of both the |
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, depending on their depositional history and environment. Their chemical composition, gradual growth, and preservation in caves make them useful paleoclimatic proxies. Chemical and physical characteristics More than 300 variations of cave mineral deposits have been identified. The vast majority of speleothems are calcareous, composed of calcium carbonate (CaCO3) minerals (calcite or aragonite). Less commonly, speleothems are made of calcium sulfate (gypsum or mirabilite) or opal. Speleothems of pure calcium carbonate or calcium sulfate are translucent and colorless. The presence of iron oxide or copper provides a reddish brown color. The presence of manganese oxide can create darker colors such as black or dark brown. Speleothems can also be brown d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Atiu Swiftlet
The Atiu swiftlet or Sawtell's Swiftlet (''Aerodramus sawtelli'') is a species of bird in the swift family, endemic to Atiu in the Cook Islands. This small, dark swift measures long. It is sooty-brown above, slightly lighter below. Its natural habitat In ecology, the term habitat summarises the array of resources, physical and biotic factors that are present in an area, such as to support the survival and reproduction of a particular species. A species habitat can be seen as the physical ...s are the island's fernlands and mixed horticultural areas over which it feeds, and in makatea limestone caves within which it nests. The species is known on Atiu as kopeka. References External links * * * * Atiu swiftlet Birds of the Cook Islands Atiu swiftlet Taxonomy articles created by Polbot {{apodiformes-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Animal Echolocation
Echolocation, also called bio sonar, is a biological sonar used by several animal species. Echolocating animals emit calls out to the environment and listen to the echoes of those calls that return from various objects near them. They use these echoes to locate and identify the objects. Echolocation is used for navigation, foraging, and hunting in various environments. Echolocating animals include some mammals (most notably Laurasiatheria) and a few birds, especially some bat species and odontocetes (toothed whales and dolphins), but also in simpler forms in other groups such as shrews, and two cave-dwelling bird groups, the so-called cave swiftlets in the genus ''Aerodramus'' (formerly ''Collocalia'') and the unrelated oilbird ''Steatornis caripensis''. Early research The term ''echolocation'' was coined in 1938 by the American zoologist Donald Griffin, who, with Robert Galambos, first demonstrated the phenomenon in bats. As Griffin described in his book, the 18th century I ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Banyan
A banyan, also spelled "banian", is a fig that develops accessory trunks from adventitious prop roots, allowing the tree to spread outwards indefinitely. This distinguishes banyans from other trees with a strangler habit that begin life as an epiphyte, i.e. a plant that grows on another plant, when its seed germinates in a crack or crevice of a host tree or edifice. "Banyan" often specifically denotes ''Ficus benghalensis'' (the "Indian banyan"), which is the national tree of India, though the name has also been generalized to denominate all figs that share a common life cycle and used systematically in taxonomy to denominate the subgenus '' Urostigma''. Characteristics Like other fig species, banyans bear their fruit in the form of a structure called a " syconium". The syconium of ''Ficus'' species supply shelter and food for fig wasps and the trees depend on the fig wasps for pollination. Frugivore birds disperse the seeds of banyans. The seeds are small, and because ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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