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Humboldt Current
The Humboldt Current, also called the Peru Current, is a cold, low-salinity ocean current that flows north along the western coast of South America. It is an eastern boundary current flowing in the direction of the equator, and extends 500–1,000 km (310–620 mi) offshore. The Humboldt Current is named after the Prussian naturalist Alexander von Humboldt. In 1846, von Humboldt reported measurements of the cold-water current in his book Cosmos. The current extends from southern Chile (~45th parallel south) to northern Peru (~4th parallel south) where cold, upwelled, waters intersect warm tropical waters to form the Equatorial Front. Sea surface temperatures off the coast of Peru, around 5th parallel south, reach temperatures as low as 16 °C (61 °F). This is highly uncharacteristic of tropical waters, as most other regions have temperatures measuring above 25 °C (77 °F). Upwelling brings nutrients to the surface, which support phytoplankton and ultimately increase biological productivity. The Humboldt Current is a highly productive ecosystem. It is the most productive eastern boundary current system. It accounts for roughly 18-20% of the total worldwide marine fish catch. The species are mostly pelagic: sardines, anchovies and jack mackerel. The system's high productivity supports other important fishery resources as well as marine mammals (eared seals and cetaceans) and seabirds. Periodically, the upwelling that drives the system's productivity is disrupted by the El Niño-Southern Oscillation (ENSO) event, often with large social and economic impacts. The Humboldt has a considerable cooling influence on the climate of Chile, Peru and Ecuador. It is also largely responsible for the aridity of Atacama Desert in northern Chile and coastal areas of Peru and also of the aridity of southern Ecuador. Marine air is cooled by the current and thus is not conducive to generating precipitation (although clouds and fog are produced).
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  • 07 Oct 2022
Topic Review
Pine Ridge Indian Reservation
The Pine Ridge Indian Reservation (Template:Lang-lkt), also called Pine Ridge Agency, is an Oglala Lakota Native American reservation located in the U.S. state of South Dakota. Originally included within the territory of the Great Sioux Reservation, Pine Ridge was created by the Act of March 2, 1889, 25 Stat. 888. in the southwest corner of South Dakota on the Nebraska border. Today it consists of 3,468.85 sq mi (8,984.3 km2) of land area and is the eighth-largest reservation in the United States, larger than Delaware and Rhode Island combined. The reservation encompasses the entirety of Oglala Lakota County and Bennett County, the southern half of Jackson County, and a small section of Sheridan County added by Executive Order No. 2980 of February 20, 1904. Of the 3,142 counties in the United States, these are among the poorest. Only 84,000 acres (340 km2) of land are suitable for agriculture. The 2000 census population of the reservation was 15,521; but a study conducted by Colorado State University and accepted by the United States Department of Housing and Urban Development has estimated the resident population to reach 28,787. Pine Ridge is the site of several events that mark milestones in the history between the Sioux of the area and the United States (U.S.) government. Stronghold Table—a mesa in what is today the Oglala-administered portion of Badlands National Park—was the location of the last of the Ghost Dances. The U.S. authorities' attempt to repress this movement eventually led to the Wounded Knee Massacre on December 29, 1890. A mixed band of Miniconjou Lakota and Hunkpapa Sioux, led by Chief Spotted Elk, sought sanctuary at Pine Ridge after fleeing the Standing Rock Agency, where Sitting Bull had been killed during efforts to arrest him. The families were intercepted by a heavily armed detachment of the Seventh Cavalry, which attacked them, killing many women and children as well as warriors. This was the last large engagement between U.S. forces and Native Americans and marked the end of the western frontier. Changes accumulated in the last quarter of the 20th century; in 1971 the Oglala Sioux Tribe (OST) started Oglala Lakota College, a tribal college, which offers 4-year degrees. In 1973 decades of discontent at the Pine Ridge Reservation resulted in a grassroots protest that escalated into the Wounded Knee Incident, gaining national attention. Members of the Oglala Lakota, the American Indian Movement and supporters occupied the town in defiance of federal and state law enforcement in a protest that turned into an armed standoff lasting 71 days. This event inspired American Indians across the country and gradually led to changes at the reservation, with a revival of some cultural traditions. In 1981 the Lakota Tim Giago started the Lakota Times at Pine Ridge, the first independent Native American newspaper in the nation; he published it until selling it in 1998. Located at the southern end of the Badlands, the reservation is part of the mixed grass prairie, an ecological transition zone between the short-grass and tall-grass prairies; all are part of the Great Plains. A great variety of plant and animal life flourishes on and adjacent to the reservation, including the endangered black-footed ferret. The area is also important in the field of paleontology; it contains deposits of Pierre Shale formed on the seafloor of the Western Interior Seaway, evidence of the marine Cretaceous–Paleogene boundary, and one of the largest deposits of fossils of extinct mammals from the Oligocene epoch.
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  • 07 Oct 2022
Topic Review
Finn River (County Fermanagh and County Monaghan)
The Finn River (Irish: An Fhinn or Abhainn na Finne), also known as the River Finn, is a small river that flows through parts of County Fermanagh and County Monaghan in the south of Ulster, the northern province in Ireland. Part of the river forms the boundary between County Fermanagh and County Monaghan, thus forming a short part of the border between Northern Ireland and the Republic of Ireland. Two very short stretches of the river, just north of Redhills and at Castle Saunderson, near Belturbet, also form part of the boundary between County Fermanagh and County Cavan. Parts of the river flow entirely within County Fermanagh, while other parts of the river flow entirely within County Monaghan. The Finn River should not be confused with the better known and much longer River Finn in County Donegal in the west of Ulster. The Finn River rises on the slopes of Slieve Beagh in the south-east of County Fermanagh, rising to the north of Roslea, a village also located in south-east Fermanagh. It initially flows in a southerly direction, meandering around both Rough Hill and Gola, two neighbouring townlands in the north-west of County Monaghan that are a short distance north-east of Roslea. The river then flows back into Fermanagh, skirting around the north-western, western and southern edges of Roslea and along the western edge of Spring Grove Forest, crossing back into County Monaghan beside New Bridge. At a place between New Bridge and Aghafin House, the river meanders around a sharp bend, flowing in a south-easterly direction for almost two miles, entirely within County Monaghan, between the townland of Aghafin, just north-east of Clones, and the townland of Nook, just south-east of Stonebridge. Thereafter, the river mainly flows in a south-westerly direction, all the way to its mouth on Upper Lough Erne. The river flows through Stonebridge and Analore, two hamlets in West Monaghan. It flows very close to Ballynure House, a now ruined Late Georgian residence just outside Analore. The Finn flows to the east, and then to the south, of Clones, the main town in West Monaghan. The river flows just to the north and north-west of the Hilton Park Demesne, near the village of Scotshouse, also in West Monaghan. The Finn flows through Wattlebridge, a hamlet in the south-east of County Fermanagh, then enters Upper Lough Erne nearby, entering the lough directly opposite Derrykerrib (Irish: Doire Ceirbe), an island and townland also in the south-east of County Fermanagh. The river flows into a narrow channel of the lough at this place, where the townland of Edergool in County Fermanagh meets the townland of Castlesaunderson Demesne, where Castle Saunderson is located, in County Cavan. Thus, half of the river's mouth is in County Fermanagh, while the other half is in County Cavan. The river's mouth, which is at the edge of the Castle Saunderson Demesne, is also very near the Lanesborough Demesne, a former demesne in the townland of Quivvy on the County Cavan shore of Upper Lough Erne. The Lanesborough Demesne, near Belturbet, is directly opposite the north-western shore of Derrykerrib Island. Traditionally, the Finn River was considered navigable for most of the year by certain types of river boat, from its mouth upstream as far as Cumber Bridge in the townland of Coolnalong (Irish: Cúil na Long), a bridge located between Scotshouse and Clones. The river meanders significantly throughout most of its course.
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  • 06 Oct 2022
Topic Review
List of Northernmost Items
This is a list of various northernmost things on earth.
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  • 06 Oct 2022
Topic Review
Global 200
The Global 200 is the list of ecoregions identified by WWF, the global conservation organization, as priorities for conservation. According to WWF, an ecoregion is defined as a "relatively large unit of land or water containing a characteristic set of natural communities that share a large majority of their species dynamics, and environmental conditions". So, for example, based on their levels of endemism, Madagascar gets multiple listings, ancient Lake Baikal gets one, and the North American Great Lakes get none. The WWF assigns a conservation status to each ecoregion in the Global 200: critical or endangered; vulnerable; and relatively stable or intact. Over half of the ecoregions in the Global 200 are rated endangered.
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Topic Review
Sulfate Minerals
The sulfate minerals are a class of minerals that include the sulfate ion (SO42−) within their structure. The sulfate minerals occur commonly in primary evaporite depositional environments, as gangue minerals in hydrothermal veins and as secondary minerals in the oxidizing zone of sulfide mineral deposits. The chromate and manganate minerals have a similar structure and are often included with the sulfates in mineral classification systems. Sulfate minerals include:
  • 599
  • 06 Oct 2022
Topic Review
Koh-i-Sultan
Koh-i-Sultan is a volcano in Balochistan, Pakistan. It is part of the tectonic belt formed by the collision of India and Asia: specifically, a segment influenced by the subduction of the Arabian plate beneath the Asian plate and forming a volcanic arc which includes the Bazman and Taftan volcanoes in Iran. The volcano consists of three main cones, with heavily eroded craters running west-northwest and surrounded by a number of subsidiary volcanic centres. Its summit is 2,334 metres (7,657 ft) high, and the crater associated with the Miri cone has a smaller crater inside. The volcano is formed by andesite and dacite rocks, with fragmentary rocks prevailing over lava flows. The rocks have typical arc-volcano chemistry and composition, with a progression from andesite to dacite in the eruption products with younger age. Potassium-argon dating has indicated an age range from 5,900,000 to 90,000 years. Subsequent erosion has generated a large debris apron around the base of the volcano and carved rock formations which impressed early explorers; one well-known rock formation is Neza e Sultan. Geothermal activity and the emission of volcanic gases are ongoing, and the volcano has been prospected for the possibility of obtaining geothermal energy. The geothermal activity has resulted in widespread rock alteration and the formation of sulfur deposits, which were mentioned in a 1909 report and later mined. Koh-i-Sultan also has deposits of other minerals.
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  • 04 Oct 2022
Topic Review
Extreme Points of Earth
This is a list of extreme points of Earth, the geographical locations that are farther north or south than, higher or lower in elevation than, or farthest inland or out to sea from, any other locations on the landmasses, continents or countries. For other lists of extreme points on Earth, including places that hold temperature and weather records, see Extremes on Earth, Lists of extreme points, and List of weather records.
  • 6.9K
  • 30 Sep 2022
Topic Review
Karratha, Western Australia
Karratha is a city in the Pilbara region of Western Australia, adjoining the port of Dampier. It was established in 1968 to accommodate the processing and exportation workforce of the Hamersley Iron mining company and, in the 1980s, the petroleum and liquefied natural gas operations of the North West Shelf Venture. At June 2018, Karratha had an urban population of 16,708. The city's name comes from the cattle station of the same name, which derives from a word in a local Aboriginal language meaning "good country" or "soft earth". The city is the seat of government of the City of Karratha, a local government area covering the surrounding region.
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  • 30 Sep 2022
Topic Review
Soil in Atsbi Wenberta
The soils of the Atsbi Wenberta woreda (district) in Tigray (Ethiopia) reflect its longstanding agricultural history, highly seasonal rainfall regime and relatively low temperatures. The northern part of the district is on the high uplifted Atsbi Horst (with metamorphic rock and consolidated Palaeozoic fluvio-glacial deposits) , whereas the southern part is dominated by the Des’a forest on Antalo Limestone. In between there is the fluvial landscape of Hayqi Meshal. Particularities in the southern part of the district are soil catenas on intervening plains behind tufa dams and in a polje.
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