|
Pica Gap
Pica gap is a segment in the Central Volcanic Zone of Chile where volcanic activity is absent. It is named after the Altos de Pica region. This segment is long and extends between the volcanoes Isluga in the north and Irruputuncu in the south. Volcanoes in the gap are old, Miocene to Pliocene in age and are heavily eroded. Examples include , Cerro Cariquima and Cerro Tatjachura. At the latitude of the Pica gap, an underwater rise known as the Iquique rise is subducted in the Peru-Chile Trench. It is unclear if the subduction of this rise is the cause for the lack of recent volcanism in the Pica gap. The lack of volcanism in the Pica gap appears to be due to unfavourable mantle flow patterns, which prevent the ascent of magma. Geologically, the Pica gap lies between two crustal domains which are defined by their divergent lead isotope ratios, the northerly Arequipa-Antofalla block of Proterozoic age and the southern Chilenia terrane of Paleozoic age. Other phenomena wh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Central Volcanic Zone
The Andean Volcanic Belt is a major volcanic belt along the Andean cordillera in Argentina, Bolivia, Chile, Colombia, Ecuador, and Peru. It is formed as a result of subduction of the Nazca Plate and Antarctic Plate underneath the South American Plate. The belt is subdivided into four main volcanic zones which are separated by volcanic gaps. The volcanoes of the belt are diverse in terms of activity style, products, and morphology. While some differences can be explained by which volcanic zone a volcano belongs to, there are significant differences within volcanic zones and even between neighboring volcanoes. Despite being a type location for calc-alkalic and subduction volcanism, the Andean Volcanic Belt has a broad range of volcano-tectonic settings, as it has rift systems and extensional zones, transpressional faults, subduction of mid-ocean ridges and seamount chains as well as a large range of crustal thicknesses and magma ascent paths and different amounts of crustal assim ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Horst (geology)
In physical geography and geology, a horst is a raised fault block bounded by Fault (geology), normal faults. Horsts are typically found together with Graben, grabens. While a horst lifted or remains stationary, the grabens on either side Subsidence, subside. This is often caused by Extensional tectonics, extensional forces pulling apart the crust. Horsts may represent features such as plateaus, mountains, or ridges on either side of a valley. Horsts can range in size from small fault-blocks, up to large regions of stable continent that have not been not folded or warped by tectonic forces. The word ''Horst'' in German language, German means "mass" or "heap," and was first used in the geological sense in 1883 by Eduard Suess in ''The Face of the Earth.''Originally published in 1883 in German as "Das Antlitz der Erde", translated and published in English in 1904 Geomorphology Horsts may have either symmetrical or asymmetrical cross-sections. If the normal faults to either side ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geothermal Activity
Geothermal activity is a group of natural heat transfer processes, occurring on Earth's surface, caused by the presence of excess heat in the subsurface of the affected area. Geothermal activity can manifest itself in a variety of different phenomena, including, among others, elevated surface temperatures, various forms of hydrothermal activity, and the presence of fumaroles that emit hot volcanic gases. Background physics Geothermal activity mostly appears in volcanic provinces, in some cases it can be caused by underground fires or by large deposits of radioactive elements. Other sources of internal heating can be gravitational differentiation of substances, tidal friction, metamorphism, or phase transitions. The release of heat to the surface occurs either in the form of a conductive heat flow, or in the form of convective heat transfer by groundwater or gases. Geothermal activity Fumaroles and vents Fumaroles, or volcanic vents, are holes in the ground from which ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alto Toroni
Sillajhuay (also known as Sillajguay or Alto Toroni) is a volcano on the border between Bolivia and Chile. It is part of a volcanic chain that stretches across the border between Bolivia and Chile and forms a mountain massif that is in part covered by ice; whether this ice should be considered a glacier is debatable but it has been retreating in recent decades. The volcano has developed on top of older ignimbrites. The volcano was active within the last one million years, but not within recent times considering the heavy glacial erosion of the mountain and the widespread periglacial modifications. Non-eruptive activity however occurs in the form of surface deformation and earthquake activity. Geography and geomorphology Sillajhuay is located in the Andes on the border between Bolivia and Chile ( commune of Pica- Colchane, Tarapaca Region) although only a small easterly sector of the mountain is located in Bolivia. The volcano lies in a thinly inhabited region; the t ... [...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] |
Ignimbrite
Ignimbrite is a type of volcanic rock, consisting of hardened tuff. Ignimbrites form from the deposits of pyroclastic flows, which are a hot suspension of particles and gases flowing rapidly from a volcano, driven by being denser than the surrounding atmosphere. New Zealand geologist Patrick Marshall (1869-1950) coined the term ''ignimbrite'' from the Latin ''igni-'' [fire] and ''imbri-'' [rain]. Ignimbrites are made of a very poorly sorted mixture of volcanic ash (or tuff when Lithification, lithified) and pumice lapilli, commonly with scattered lithic fragments. The ash is composed of glass shards and crystal fragments. Ignimbrites may be loose and unconsolidated, or lithified (solidified) rock called lapilli-tuff. Near the volcanic source, ignimbrites often contain thick accumulations of lithic blocks, and distally, many show meter-thick accumulations of rounded cobbles of pumice. Ignimbrites may be white, grey, pink, beige, brown, or black depending on their composition and d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lava Dome
In volcanology, a lava dome is a circular mound-shaped protrusion resulting from the slow extrusion of viscous lava from a volcano. Dome-building eruptions are common, particularly in convergent plate boundary settings. Around 6% of eruptions on Earth are lava dome forming. The geochemistry of lava domes can vary from basalt (e.g. Semeru, 1946) to rhyolite (e.g. Chaiten, 2010) although the majority are of intermediate composition (such as Santiaguito, dacite-andesite, present day) The characteristic dome shape is attributed to high viscosity that prevents the lava from flowing very far. This high viscosity can be obtained in two ways: by high levels of silica in the magma, or by degassing of fluid magma. Since viscous basaltic and andesitic domes weather fast and easily break apart by further input of fluid lava, most of the preserved domes have high silica content and consist of rhyolite or dacite. Existence of lava domes has been suggested for some domed structures on the Mo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cerro Porquesa
Cerro Porquesa ( Aymara) is an approximately high ( above base) rhyodacite lava dome in the Andes. It has a oval outline, and is high. The lava dome is accompanied by block-and-ash flows and lava flows and the presence of two volcanic cones has been reported. The lava dome is of Pliocene/ Pleistocene age with little glacial features on the younger domes indicating young ages. The Quebrada de Piga, which flows to Salar de Huasco, originates at Cerro Porquesa. The dome was formed in at least three different eruption stages, with each stage contributing about two or three different lobes. Further, a rhyolitic ignimbrite with 69.5% SiO2 may be linked to the domes. It fills a valley in the south of the complex about thick. This ignimbrite is dated 0.73±0.16 and 0.63 +0.92/-0.63 mya by potassium-argon dating in biotite, although with low precision. Another 0.28 mya old ignimbrite was originally attributed to Porquesa but instead comes from a wide caldera in Bolivia. Three d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arica
Arica ( ; ) is a Communes of Chile, commune and a port city with a population of 222,619 in the Arica Province of northern Chile's Arica y Parinacota Region. It is Chile's northernmost city, being located only south of the border with Peru. The city is the capital (political), capital of both the Arica Province and the Arica and Parinacota Region. Arica is located at the orocline, bend of South America's western coast known as the Arica Bend or Arica Elbow. At the location of the city are two valleys that dissect the Atacama Desert converge: Azapa Valley, Azapa and Lluta River, Lluta. These valleys provide citrus and olives for export. Arica is an important port for a large inland region of South America. The city serves a free port for Bolivia and manages a substantial part of that country's trade.In addition it is the end station of the Bolivian oil pipeline beginning in Oruro, Bolivia, Oruro. The city's strategic position is enhanced by being next to the Chile Route 5, Pan-Ame ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Salar De Uyuni
Salar de Uyuni (or "Salar de Tunupa") is the world's largest salt flat, or playa, at over in area. It is in the Daniel Campos Province in Potosí in southwest Bolivia, near the crest of the Andes at an elevation of above sea level. The Salar was formed as a result of transformations between several prehistoric lakes that existed around forty thousand years ago but had all evaporated over time. It is now covered by a few meters of salt crust, which has an extraordinary flatness with the average elevation variations within one meter over the entire area of the Salar. The crust serves as a source of salt and covers a pool of brine, which is exceptionally rich in lithium. The large area, clear skies, and exceptional flatness of the surface make the Salar ideal for calibrating the altimeters of Earth observation satellites. Following rain, a thin layer of dead calm water transforms the flat into the world's largest mirror, across. The Salar serves as the major transport route a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Andes
The Andes, Andes Mountains or Andean Mountains (; ) are the longest continental mountain range in the world, forming a continuous highland along the western edge of South America. The range is long, wide (widest between 18°S – 20°S latitude), and has an average height of about . The Andes extend from north to south through seven South American countries: Venezuela, Colombia, Ecuador, Peru, Bolivia, Chile, and Argentina. Along their length, the Andes are split into several ranges, separated by intermediate depressions. The Andes are the location of several high plateaus—some of which host major cities such as Quito, Bogotá, Cali, Arequipa, Medellín, Bucaramanga, Sucre, Mérida, El Alto and La Paz. The Altiplano plateau is the world's second-highest after the Tibetan plateau. These ranges are in turn grouped into three major divisions based on climate: the Tropical Andes, the Dry Andes, and the Wet Andes. The Andes Mountains are the highest m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Seismic Velocity
A seismic wave is a wave of acoustic energy that travels through the Earth. It can result from an earthquake, volcanic eruption, magma movement, a large landslide, and a large man-made explosion that produces low-frequency acoustic energy. Seismic waves are studied by seismologists, who record the waves using seismometers, hydrophones (in water), or accelerometers. Seismic waves are distinguished from seismic noise (ambient vibration), which is persistent low-amplitude vibration arising from a variety of natural and anthropogenic sources. The propagation velocity of a seismic wave depends on density and elasticity of the medium as well as the type of wave. Velocity tends to increase with depth through Earth's crust and mantle, but drops sharply going from the mantle to Earth's outer core. Earthquakes create distinct types of waves with different velocities. When recorded by a seismic observatory, their different travel times help scientists locate the quake's hypocenter ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
.JPG "Click for more on -> Arica")
.jpg "Click for more on -> Andes")
