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Geology Of Ghana
The geology of Ghana is primarily very ancient crystalline basement rock, volcanic belts and sedimentary basins, affected by periods of igneous activity and two major orogeny mountain building events. Aside from modern sediments and some rocks formed within the past 541 million years of the Phanerozoic Eon, along the coast, many of the rocks in Ghana formed close to one billion years ago or older leading to five different types of gold deposit formation, which gave the region its former name Gold Coast (region), Gold Coast. Stratigraphy, Tectonics & Geologic History Ancient rocks from the Paleoproterozoic, Neoproterozoic and perhaps early Paleozoic cover almost all of Ghana, except near the coast where Paleozoic, Mesozoic and Cenozoic rocks are common. Main Precambrian rock units include the metamorphosed and fold (geology), folded Dahomeyan, Birimian, Tarkwaian system (geology), System, Togo series (geology), Series, and the Buem formation (geology), Formation. Paleozoic rocks i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Jubilee Field 002
A jubilee is a particular anniversary of an event, usually denoting the 25th, 40th, 50th, 60th, and the 70th anniversary. The term is often now used to denote the celebrations associated with the reign of a monarch after a milestone number of years have passed. Religious usage The Jubilee ( he, יובל ''yovel'') year (every 50th year) and the Shmita, Sabbatical year (every seventh year) are Biblical commandments concerning ownership of land and slaves. The laws concerning the Sabbatical year are still observed by many religious Jews in the State of Israel, while the Jubilee has not been observed for many centuries. According to the Hebrew Bible, every seventh year, farmers in the land of Israel are commanded to let their land lie fallow, and slaves were freed. The celebration of the Jubilee is the fiftieth year, that is, the year after seven Sabbatical cycles. In Catholic Church, Roman Catholic tradition, a Jubilee is a year of Sacrament of Penance, remission of sins and al ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tuff
Tuff is a type of rock made of volcanic ash ejected from a vent during a volcanic eruption. Following ejection and deposition, the ash is lithified into a solid rock. Rock that contains greater than 75% ash is considered tuff, while rock containing 25% to 75% ash is described as tuffaceous (for example, ''tuffaceous sandstone''). Tuff composed of sandy volcanic material can be referred to as volcanic sandstone. Tuff is a relatively soft rock, so it has been used for construction since ancient times. Because it is common in Italy, the Romans used it often for construction. The Rapa Nui people used it to make most of the ''moai'' statues on Easter Island. Tuff can be classified as either igneous or sedimentary rock. It is usually studied in the context of igneous petrology, although it is sometimes described using sedimentological terms. Tuff is often erroneously called tufa in guidebooks and in television programmes. Volcanic ash The material that is expelled in a volcanic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dacite
Dacite () is a volcanic rock formed by rapid solidification of lava that is high in silica and low in alkali metal oxides. It has a fine-grained (aphanitic) to porphyritic texture and is intermediate in composition between andesite and rhyolite. It is composed predominantly of plagioclase feldspar and quartz. Dacite is relatively common, occurring in many tectonic settings. It is associated with andesite and rhyolite as part of the subalkaline volcanic rock, subalkaline tholeiite, tholeiitic and calc-alkaline magma series. Composition Dacite consists mostly of plagioclase feldspar and quartz with biotite, hornblende, and pyroxene (augite or enstatite). The quartz appears as rounded, corroded phenocrysts, or as an element of the ground-mass. The plagioclase in dacite ranges from oligoclase to andesine and labradorite. Sanidine occurs, although in small proportions, in some dacites, and when abundant gives rise to rocks that form rhyodacite, transitions to the rhyolites. The rel ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ashanti Belt
Ashanti may refer to: * Ashanti people, an ethnic group in West Africa ** Ashanti Empire, a pre-colonial West African state in what is now southern Ghana ** Ashanti dialect or Asante, a literary dialect of the Akan language of southern Ghana ** Ashanti Region, a region within Ghana ** Ashanti (Crown Colony), a United Kingdom colony 1901–1957 in what is now Ghana * Ashanti (singer) (born 1980), American singer-songwriter and actress ** ''Ashanti'' (album), a 2002 album by Ashanti * ''Ashanti'' (1979 film), an American film * ''Ashanti'' (1982 film), an Indian film * HMS ''Ashanti'' (F51), a Tribal-class destroyer launched in 1937 * HMS ''Ashanti'' (F117), a Tribal-class frigate launched in 1959 People with the given name * Ashanti Alston (born 1954), former Black Panther Party member * Ashanti Johnson, American geochemist and chemical oceanographer * Ashanti Obi (born 1952), Nigerian sprinter See also * Asante (other) * Ashanti Gold SC, a football club in Obuasi, A ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lawra Belt
Lawra is a small town and is the capital of Lawra district, a district in the Upper West Region of Ghana.Lawra District Location The town is located in the North western part of Ghana. Its distance from Wa, the Regional capital by road is 88.55 Kilometers (55.02 miles).History The town was an administrative centre for the historic British empire. The ruins of a large mansion from the empire still, rather incongruously, remain.Politics Lawra is in the Lawra constituency headed by Hon. Anthony Nyoh-Abeyifaa Karbo of the |
Metamorphism
Metamorphism is the transformation of existing rock (the protolith) to rock with a different mineral composition or texture. Metamorphism takes place at temperatures in excess of , and often also at elevated pressure or in the presence of chemically active fluids, but the rock remains mostly solid during the transformation. Metamorphism is distinct from weathering or diagenesis, which are changes that take place at or just beneath Earth's surface. Various forms of metamorphism exist, including regional, contact, hydrothermal, shock, and dynamic metamorphism. These differ in the characteristic temperatures, pressures, and rate at which they take place and in the extent to which reactive fluids are involved. Metamorphism occurring at increasing pressure and temperature conditions is known as ''prograde metamorphism'', while decreasing temperature and pressure characterize ''retrograde metamorphism''. Metamorphic petrology is the study of metamorphism. Metamorphic petrologists re ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tholeiitic Magma Series
The tholeiitic magma series is one of two main magma series in subalkaline igneous rocks, the other being the calc-alkaline series. A magma series is a chemically distinct range of magma compositions that describes the evolution of a mafic magma into a more evolved, silica rich end member. Rock types of the tholeiitic magma series include tholeiitic basalt, ferro-basalt, tholeiitic basaltic andesite, tholeiitic andesite, dacite and rhyolite. The variety of basalt in the series was originally called ''tholeiite'' but the International Union of Geological Sciences recommends that ''tholeiitic basalt'' be used in preference to that term.Le Maitre ''et al.'' 2002 Tholeiitic rock types tend to be more enriched in iron and less enriched in aluminium than calc-alkaline rock types. They are thought to form in a less oxidized environment than calc-alkaline rocks. Tholeiitic basalt is formed at mid-ocean ridges and makes up much of the oceanic crust. Almost all the basalt found on the M ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Shale
Shale is a fine-grained, clastic sedimentary rock formed from mud that is a mix of flakes of clay minerals (hydrous aluminium phyllosilicates, e.g. kaolin, Al2 Si2 O5( OH)4) and tiny fragments (silt-sized particles) of other minerals, especially quartz and calcite.Blatt, Harvey and Robert J. Tracy (1996) ''Petrology: Igneous, Sedimentary and Metamorphic'', 2nd ed., Freeman, pp. 281–292 Shale is characterized by its tendency to split into thin layers ( laminae) less than one centimeter in thickness. This property is called '' fissility''. Shale is the most common sedimentary rock. The term ''shale'' is sometimes applied more broadly, as essentially a synonym for mudrock, rather than in the more narrow sense of clay-rich fissile mudrock. Texture Shale typically exhibits varying degrees of fissility. Because of the parallel orientation of clay mineral flakes in shale, it breaks into thin layers, often splintery and usually parallel to the otherwise indistinguishable beddin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
