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Bamboutos Mountains
The Bambouto massif or Bamboutos Mountains is a group of volcanoes based on a swell in the Cameroon Volcanic Line, located in the Western High Plateau of Cameroon, merging in the north with the Oku Volcanic Field. Geology The large volcanic complex extends in a NE-SW direction for over 50 km, with the highest peaks rising to 2,679 m around the rim of a caldera with diameter 10 km. Lava dating gives ages from 23 to 6 million years ago, with a lower basaltic series and an upper series of trachyte Trachyte () is an extrusive igneous rock composed mostly of alkali feldspar. It is usually light-colored and aphanitic (fine-grained), with minor amounts of mafic minerals, and is formed by the rapid cooling of lava enriched with silica and al ...s, trachyphonolites and phonolites. Environment The upper part of the massif above 2,000 m has a cool and cloudy climate with 2,510 mm of rainfall annually. Soils are acidic, low in phosphates and relatively infert ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Western High Plateau
The Western High Plateau, Western Highlands or Bamenda Grassfields is a region of Cameroon characterised by high relief, cool temperatures, heavy rainfall and savanna vegetation. The region lies along the Cameroon line and consists of mountain ranges and volcanoes made of crystalline and igneous rock. The region borders the South Cameroon Plateau to the southeast, the Adamawa Plateau to the northeast and the Cameroon coastal plain to the south. Topography and geology The Western High Plateau lies along the Cameroon line, a series of volcanic swells running from the Atlantic Ocean in the southwestern part of the plateau to the Adamawa Plateau in the northeast. The region is characterised by accidented relief of massifs and mountains. The Western High Plateau features several dormant volcanoes, including the Bamboutos Mountains, Mount Oku and Mount Kupe. The plateau rises in steps from the west. To the east, it terminates in mountains that range from 1,000 metres to 2,500 met ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cameroon
Cameroon (; french: Cameroun, ff, Kamerun), officially the Republic of Cameroon (french: République du Cameroun, links=no), is a country in west-central Africa. It is bordered by Nigeria to the west and north; Chad to the northeast; the Central African Republic to the east; and Equatorial Guinea, Gabon and the Republic of the Congo to the south. Its coastline lies on the Bight of Biafra, part of the Gulf of Guinea and the Atlantic Ocean. Due to its strategic position at the crossroads between West Africa and Central Africa, it has been categorized as being in both camps. Its nearly 27 million people speak 250 native languages. Early inhabitants of the territory included the Sao civilisation around Lake Chad, and the Baka hunter-gatherers in the southeastern rainforest. Portuguese explorers reached the coast in the 15th century and named the area ''Rio dos Camarões'' (''Shrimp River''), which became ''Cameroon'' in English. Fulani soldiers founded the Adamawa Emirate ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oku Volcanic Field
Oku or OKU may refer to: *Oku, Cameroon, subdivision in the Northwest Region of Cameroon ** Lake Oku, a crater lake on the Bamenda Plateau in the Northwest Region of Cameroon ** Mount Oku, the largest volcano in the Oku Massif, in the Cameroon Volcanic Line *Oku language, a Grassfields Bantu language of Cameroon *Oku people (Sierra Leone), an ethnic group of Yoruba descent in Sierra Leone. *Ökü, a village in Azerbaijan *Oku District, Okayama, a former district located in Okayama Prefecture, Japan **Oku, Okayama, a former town in the district, merged with other towns to create the city of Setouchi *Oku (surname), a common Japanese surname *Princess Ōku (661–702), a Japanese princess during the Asuka period in Japanese history *OKU, IATA Airport Code for Mokuti Lodge Airport in Namibia *Ogan Komering Ulu Regency, a province in South Sumatra, Indonesia See also *Oku Station (other) Oku Station may refer to: * Oku Station (Tokyo) - (尾久駅) A station connected with To ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Basaltic
Basalt (; ) is an aphanitic (fine-grained) extrusive igneous rock formed from the rapid cooling of low-viscosity lava rich in magnesium and iron (mafic lava) exposed at or very near the surface of a rocky planet or moon. More than 90% of all volcanic rock on Earth is basalt. Rapid-cooling, fine-grained basalt is chemically equivalent to slow-cooling, coarse-grained gabbro. The eruption of basalt lava is observed by geologists at about 20 volcanoes per year. Basalt is also an important rock type on other planetary bodies in the Solar System. For example, the bulk of the plains of Venus, which cover ~80% of the surface, are basaltic; the lunar maria are plains of flood-basaltic lava flows; and basalt is a common rock on the surface of Mars. Molten basalt lava has a low viscosity due to its relatively low silica content (between 45% and 52%), resulting in rapidly moving lava flows that can spread over great areas before cooling and solidifying. Flood basalts are thick sequence ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trachyte
Trachyte () is an extrusive igneous rock composed mostly of alkali feldspar. It is usually light-colored and aphanitic (fine-grained), with minor amounts of mafic minerals, and is formed by the rapid cooling of lava enriched with silica and alkali metals. It is the volcanic equivalent of syenite. Trachyte is common wherever alkali magma is erupted, including in late stages of ocean island volcanismMacDonald 1983, pp. 51-52 and in continental rift valleys, above mantle plumes,Philpotts and Ague 2009, pp. 390-394 and in areas of back-arc extension. Trachyte has also been found in Gale crater on Mars. Trachyte has been used as decorative building stone and was extensively used as dimension stone in the Roman Empire and the Republic of Venice. Chemical composition Trachyte has a silica content of 60 to 65% and an alkali oxide content of over 7%. This gives it less SiO2 than rhyolite and more (Na2O plus K2O) than dacite. These chemical differences are consistent with the positio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phonolite
Phonolite is an uncommon extrusive rock, of intermediate chemical composition between felsic and mafic, with texture ranging from aphanitic (fine-grained) to porphyritic (mixed fine- and coarse-grained). Phonolite is a variation of the igneous rock trachyte that contains nepheline or leucite rather than quartz. Its intrusive equivalent is nepheline syenite. Phonolite is typically fine grained and compact. The name ''phonolite'' comes from the Ancient Greek meaning "sounding stone" due to the metallic sound it produces if an unfractured plate is hit; hence, the English name ''clinkstone'' is given as a synonym. Formation Unusually, phonolite forms from magma with a relatively low silica content, generated by low degrees of partial melting (less than 10%) of highly aluminous rocks of the lower crust such as tonalite, monzonite and metamorphic rocks. Melting of such rocks to a very low degree promotes the liberation of aluminium, potassium, sodium and calcium by melting of f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
