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Pampa Luxsar
Pampa Luxsar is a little known volcanic field located in Bolivia, southwest of the Salar de Uyuni. It consists of a field of lava flows that cover a surface area of . Cones are also found within the field, although vents are difficult to discern. The lava flows partly coalesce and are of uniform appearance, despite differences in their albedo. The field is constructed by basaltic andesite and andesite. The activity of the field may have been controlled by faults, which were later buried by lava flows. The field surrounds the older stratovolcanoes Cerro Luxsar and Cerro Uquila, which are heavily eroded. It was erupted over several stages, with the youngest being of Pleistocene or Holocene age. One vent known as Cerro Negro is a maar and probably formed under the influence of paleolakes such as Lake Minchin or Lake Tauca, which have left lake terraces in the region. See also * List of volcanoes in Bolivia The country of Bolivia hosts numerous activeIn vulcanology and this ar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bolivia
, image_flag = Bandera de Bolivia (Estado).svg , flag_alt = Horizontal tricolor (red, yellow, and green from top to bottom) with the coat of arms of Bolivia in the center , flag_alt2 = 7 × 7 square patchwork with the (top left to bottom right) diagonals forming colored stripes (green, blue, purple, red, orange, yellow, white, green, blue, purple, red, orange, yellow, from top right to bottom left) , other_symbol = , other_symbol_type = Dual flag: , image_coat = Escudo de Bolivia.svg , national_anthem = " National Anthem of Bolivia" , image_map = BOL orthographic.svg , map_width = 220px , alt_map = , image_map2 = , alt_map2 = , map_caption = , capital = La Paz Sucre , largest_city = , official_languages = Spanish , languages_type = Co-official languages , languages ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stratovolcano
A stratovolcano, also known as a composite volcano, is a conical volcano built up by many layers (strata) of hardened lava and tephra. Unlike shield volcanoes, stratovolcanoes are characterized by a steep profile with a summit crater and periodic intervals of explosive eruptions and effusive eruptions, although some have collapsed summit craters called calderas. The lava flowing from stratovolcanoes typically cools and hardens before spreading far, due to high viscosity. The magma forming this lava is often felsic, having high-to-intermediate levels of silica (as in rhyolite, dacite, or andesite), with lesser amounts of less-viscous mafic magma. Extensive felsic lava flows are uncommon, but have travelled as far as . Stratovolcanoes are sometimes called composite volcanoes because of their composite stratified structure, built up from sequential outpourings of erupted materials. They are among the most common types of volcanoes, in contrast to the less common shield volca ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
List Of Volcanoes In Bolivia
The country of Bolivia hosts numerous activeIn vulcanology and this article active volcanoes are those with Holocene eruption, that means eruptions in the last 10,000 years. and extinct volcanoes across its territory. The active volcanoes are in western Bolivia making up the Cordillera Occidental, the western limit of the Altiplano plateau. Many of the active volcanoes are international mountains shared with Chile. All Cenozoic volcanoes of Bolivia are part of the Central Volcanic Zone (CVZ) of the Andean Volcanic Belt that results due to processes involved in the subduction of Nazca Plate under the South American Plate. The Central Volcanic Zone is a major upper Cenozoic volcanic province. Apart from Andean volcanoes the geology of Bolivia host the remnants of ancient volcanoes around the Precambrian Guaporé Shield in the eastern part of the country. Image:Nevado Sajama.jpg, Sajama, a stratovolcano considered extinct. Image:Licancabur Green Lake.jpg, View of Licancabur. Th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Terrace (geology)
In geology, a terrace is a step-like landform. A terrace consists of a flat or gently sloping geomorphic surface, called a tread, that is typically bounded on one side by a steeper ascending slope, which is called a "riser" or "scarp". The tread and the steeper descending slope (riser or scarp) together constitute the terrace. Terraces can also consist of a tread bounded on all sides by a descending riser or scarp. A narrow terrace is often called a bench.Howard, A.D., R.W. Fairbridge, J.H. Quinn, 1968, "Terraces, Fluvial—Introduction", in R.W. Fairbridge, ed., ''The Encyclopedia of Geomorphology: Encyclopedia of Earth Science Series'', vol. 3. Reinhold Book Corporation. New York, New York.Jackson, J.A., 1997, ''Glossary of Geology''. American Geological Institute. Alexandria, Virginia. The sediments underlying the tread and riser of a terrace are also commonly, but incorrectly, called terraces, leading to confusion. Terraces are formed in various ways. Fluvial terraces ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lake Tauca
Lake Tauca is a former lake in the Altiplano of Bolivia. It is also known as Lake Pocoyu for its constituent lakes: Lake Poopó, Salar de Coipasa and Salar de Uyuni. The lake covered large parts of the southern Altiplano between the Eastern Cordillera and the Western Cordillera, covering an estimated of the basins of present-day Lake Poopó and the Salars of Uyuni, Coipasa and adjacent basins. Water levels varied, possibly reaching in altitude. The lake was saline. The lake received water from Lake Titicaca, but whether this contributed most of Tauca's water or only a small amount is controversial; the quantity was sufficient to influence the local climate and depress the underlying terrain with its weight. Diatoms, plants and animals developed in the lake, sometimes forming reef knolls. The duration of Lake Tauca's existence is uncertain. Research in 2011 indicated that the rise in lake levels began 18,500 BP, peaking 16,000 and 14,500 years ago. About 14,200 years ago, la ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lake Minchin
Lake Minchin is a name of an ancient lake in the Altiplano of South America. It existed where today the Salar de Uyuni, Salar de Coipasa and Lake Poopó lie. It was formerly considered the highest lake in the Altiplano but research indicated that the highest shoreline belongs to the later Lake Tauca instead. The concept of a "Lake Minchin" was first coined in 1906 and the name is based on John B. Minchin. The dating of the lake varies but probably lasted until 22,000 – 21,000 BP. A glacier advance was in progress in the Andes during that time period. The name "Minchin" has also been used in other contexts, and it has been proposed that the lake was actually a combination of several different paleolakes. Definition The name "Lake Minchin" has been used inconsistently to refer to either a lake existing 45,000 years ago, the highest lake in the Altiplano, or to sediment formations. This confusion has led to calls to drop the usage of the name "Minchin". An alternative theory ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Maar
A maar is a broad, low-relief volcanic crater caused by a phreatomagmatic eruption (an explosion which occurs when groundwater comes into contact with hot lava or magma). A maar characteristically fills with water to form a relatively shallow crater lake which may also be called a maar. The name comes from a Moselle Franconian dialect word used for the circular lakes of the Daun area of Germany. Notes: * According to German Wikipedia's ''"Maar"'' article, in 1544 in his book ''Cosmographia'', Sebastian Münster (1488–1552) first applied the word "maar" (as ''Marh'') to the Ulmener Maar and the Laacher See. See: Sebastian Münster, ''Cosmographia'' (Basel, Switzerland: Heinrich Petri, 1544)p. 341. From p. 341: ''"Item zwen namhafftiger seen seind in der Eyfel / einer bey de schloß Ulmen / und ein ander bey dem Closter züm Laich / die seind sere tieff / habe kein ynflüß aber vil außflüß / die nennet man Marh unnd seind fischreich."'' (Also two noteworthy lakes are ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pleistocene
The Pleistocene ( , often referred to as the ''Ice age'') is the geological Epoch (geology), epoch that lasted from about 2,580,000 to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was finally confirmed in 2009 by the International Union of Geological Sciences, the cutoff of the Pleistocene and the preceding Pliocene was regarded as being 1.806 million years Before Present (BP). Publications from earlier years may use either definition of the period. The end of the Pleistocene corresponds with the end of the last glacial period and also with the end of the Paleolithic age used in archaeology. The name is a combination of Ancient Greek grc, label=none, πλεῖστος, pleīstos, most and grc, label=none, καινός, kainós (latinized as ), 'new'. At the end of the preceding Pliocene, the previously isolated North and South American continents were joined by the Isthmus of Panama, causing Great American Interchang ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fault (geology)
In geology, a fault is a planar fracture or discontinuity in a volume of rock across which there has been significant displacement as a result of rock-mass movements. Large faults within Earth's crust result from the action of plate tectonic forces, with the largest forming the boundaries between the plates, such as the megathrust faults of subduction zones or transform faults. Energy release associated with rapid movement on active faults is the cause of most earthquakes. Faults may also displace slowly, by aseismic creep. A ''fault plane'' is the plane that represents the fracture surface of a fault. A ''fault trace'' or ''fault line'' is a place where the fault can be seen or mapped on the surface. A fault trace is also the line commonly plotted on geologic maps to represent a fault. A ''fault zone'' is a cluster of parallel faults. However, the term is also used for the zone of crushed rock along a single fault. Prolonged motion along closely spaced faults can blur the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Volcanic Field
A volcanic field is an area of Earth's crust that is prone to localized volcanic activity. The type and number of volcanoes required to be called a "field" is not well-defined. Volcanic fields usually consist of clusters of up to 100 volcanoes such as cinder cones. Lava flows may also occur. They may occur as a monogenetic volcanic field or a polygenetic volcanic field. Description Alexander von Humboldt observed in 1823 that geologically young volcanoes are not distributed uniformly across the Earth's surface, but tend to be clustered into specific regions. Young volcanoes are rarely found within cratons, but are characteristic of subduction zones, rift zones, or in ocean basins. Intraplate volcanoes are clustered along hotspot traces. Within regions of volcanic activity, volcanic fields are clusters of volcanoes that share a common magma source. Scoria cones are particularly prone to cluster into volcanic fields, which are typically in diameter and consist of several tens ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Andesite
Andesite () is a volcanic rock of intermediate composition. In a general sense, it is the intermediate type between silica-poor basalt and silica-rich rhyolite. It is fine-grained (aphanitic) to porphyritic in texture, and is composed predominantly of sodium-rich plagioclase plus pyroxene or hornblende. Andesite is the extrusive equivalent of plutonic diorite. Characteristic of subduction zones, andesite represents the dominant rock type in island arcs. The average composition of the continental crust is andesitic. Along with basalts, andesites are a component of the Martian crust. The name ''andesite'' is derived from the Andes mountain range, where this rock type is found in abundance. It was first applied by Christian Leopold von Buch in 1826. Description Andesite is an aphanitic (fine-grained) igneous rock that is intermediate in its content of silica and low in alkali metals. It has less than 20% quartz and 10% feldspathoid by volume, with at least 65% of the fe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Basaltic Andesite
Basaltic andesite is a volcanic rock that is intermediate in composition between basalt and andesite. It is composed predominantly of augite and plagioclase. Basaltic andesite can be found in volcanoes around the world, including in Central America and the Andes of South America. Description Basaltic andesite is a fine-grained (aphanitic) igneous rock that is moderately low in silica and low in alkali metal oxides. It is not separately defined in the QAPF classification, which is based on the relative percentages of quartz, alkali feldspar, plagioclase feldspar, and feldspathoids, but would fall in the basalt-andesite field. This corresponds to rock in which feldspathoid makes up less than 10% and quartz less than 20% of the total QAPF fraction, and in which at least 65% of the feldspar is plagioclase. Basaltic andesite would be further distinguished from basalt and andesite by a silica content between 52% and 57%. Although classification by mineral content is preferred by the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
