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Mountain Chain
A mountain chain is a row of high mountain summits, a linear sequence of interconnected or related mountains,Whittow, John (1984). ''Dictionary of Physical Geography''. London: Penguin, p 87. . or a contiguous ridge of mountains within a larger mountain range. The term is also used for elongated fold mountains with several parallel chains ("chain mountains"). While in mountain ranges, the term mountain chain is common, in hill ranges a sequence of hills tends to be referred to a ridge or hill chain. Elongated mountain chains occur most frequently in the orogeny of fold mountains, (that are folded by lateral pressure), and nappe belts (where a sheetlike body of rock has been pushed over another rock mass). Other types of range such as horst (geology), horst ranges, fault block mountain or truncated uplands rarely form parallel mountain chains. However, if a truncated upland is eroded into a high table land, the incision of valleys can lead to the formations of mountain or hill chai ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Folding (geology)
In structural geology, a fold is a stack of originally planar surfaces, such as sedimentary rock, sedimentary stratum, strata, that are bent or curved (''"folded"'') during permanent deformation (engineering), deformation. Folds in rocks vary in size from microscopic crinkles to mountain-sized folds. They occur as single isolated folds or in periodic sets (known as ''fold trains''). wikt:synsedimentary, Synsedimentary folds are those formed during sedimentary deposition. Folds form under varied conditions of stress (physics), stress, pore pressure, and temperature gradient, as evidenced by their presence in soft sedimentary rock, sediments, the full spectrum of metamorphic rocks, and even as primary flow structures in some igneous rocks. A set of folds distributed on a regional scale constitutes a fold belt, a common feature of orogeny, orogenic zones. Folds are commonly formed by shortening of existing layers, but may also be formed as a result of displacement on a non-planar f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Central Alps
The Alps form a large mountain range dominating Central Europe, including parts of Italy, France, Switzerland, Liechtenstein, Austria, Slovenia, Germany and Hungary. This article describes the delimitation of the Alps as a whole and of subdivisions of the range, follows the course of the main chain of the Alps and discusses the lakes and glaciers found in the region. Boundaries In some areas, such as the edge of the Po Basin, the edge of the Alps is unambiguous, but where the Alps border on other mountainous or hilly regions, the border may be harder to place. These neighbouring ranges include the Apennines, the Massif Central, the Jura, the Black Forest, the Bohemian Forest, the Carpathians, and the mountains of the Balkan Peninsula. The boundary between the Apennines and the Alps is usually taken to be the Colle di Cadibona, at 435 m above sea level, above Savona on the Italian coast. The Rhône forms a clear boundary between the tectonically-formed Alps and the lar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Overthrust
A thrust fault is a break in the Earth's crust, across which older rocks are pushed above younger rocks. Thrust geometry and nomenclature Reverse faults A thrust fault is a type of reverse fault that has a dip of 45 degrees or less. If the angle of the fault plane is lower (often less than 15 degrees from the horizontal) and the displacement of the overlying block is large (often in the kilometer range) the fault is called an ''overthrust'' or ''overthrust fault''. Erosion can remove part of the overlying block, creating a ''fenster'' (or ''window'') – when the underlying block is exposed only in a relatively small area. When erosion removes most of the overlying block, leaving island-like remnants resting on the lower block, the remnants are called ''klippen'' (singular '' klippe''). Blind thrust faults If the fault plane terminates before it reaches the Earth's surface, it is called a ''blind thrust'' fault. Because of the lack of surface evidence, blind thrust fau ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Syncline
In structural geology, a syncline is a fold with younger layers closer to the center of the structure, whereas an anticline is the inverse of a syncline. A synclinorium (plural synclinoriums or synclinoria) is a large syncline with superimposed smaller folds. Synclines are typically a downward fold (synform), termed a synformal syncline (i.e. a trough), but synclines that point upwards can be found when strata have been overturned and folded (an antiformal syncline). Characteristics On a geologic map, synclines are recognized as a sequence of rock layers, with the youngest at the fold's center or ''hinge'' and with a reverse sequence of the same rock layers on the opposite side of the hinge. If the fold pattern is circular or elongate, the structure is a basin. Folds typically form during crustal deformation as the result of compression that accompanies orogenic mountain building. Notable examples * Powder River Basin, Wyoming, US * Sideling Hill roadcut along Inters ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Metamorphic Rock
Metamorphic rocks arise from the transformation of existing rock to new types of rock in a process called metamorphism. The original rock ( protolith) is subjected to temperatures greater than and, often, elevated pressure of or more, causing profound physical or chemical changes. During this process, the rock remains mostly in the solid state, but gradually recrystallizes to a new texture or mineral composition. The protolith may be an igneous, sedimentary, or existing metamorphic rock. Metamorphic rocks make up a large part of the Earth's crust and form 12% of the Earth's land surface. They are classified by their protolith, their chemical and mineral makeup, and their texture. They may be formed simply by being deeply buried beneath the Earth's surface, where they are subject to high temperatures and the great pressure of the rock layers above. They can also form from tectonic processes such as continental collisions, which cause horizontal pressure, friction, and dist ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sediment
Sediment is a solid material that is transported to a new location where it is deposited. It occurs naturally and, through the processes of weathering and erosion, is broken down and subsequently sediment transport, transported by the action of wind, water, or ice or by the force of gravity acting on the particles. For example, sand and silt can be carried in suspension (chemistry), suspension in river water and on reaching the sea bed deposited by sedimentation; if buried, they may eventually become sandstone and siltstone (sedimentary rocks) through lithification. Sediments are most often transported by water (fluvial, fluvial processes), but also wind (aeolian processes) and glaciers. Beach sands and stream channel, river channel deposits are examples of fluvial transport and deposition (geology), deposition, though sediment also often settles out of slow-moving or standing water in lakes and oceans. Desert sand dunes and loess are examples of aeolian transport and deposition. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plutonic Rock
Intrusive rock is formed when magma penetrates existing rock, crystallizes, and solidifies underground to form ''intrusions'', such as batholiths, dikes, sills, laccoliths, and volcanic necks.Intrusive RocksIntrusive rocks accessdate: March 27, 2017.Igneous intrusive rocks, accessdate: March 27, 2017.Britannica.comintrusive rock , geology , Britannica.com accessdate: March 27, 2017. Intrusion is one of the two ways igneous rock can form. The other is extrusion, such as a volcanic eruption or similar event. An intrusion is any body of intrusive igneous rock, formed from magma that cools and solidifies within the crust of the planet. In contrast, an ''extrusion'' consists of extrusive rock, formed above the surface of the crust. Some geologists use the term plutonic rock synonymously with intrusive rock, but other geologists subdivide intrusive rock, by crystal size, into coarse-grained plutonic rock (typically formed deeper in the Earth's crust in batholiths or stocks) and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plate Tectonics
Plate tectonics (, ) is the scientific theory that the Earth's lithosphere comprises a number of large tectonic plates, which have been slowly moving since 3–4 billion years ago. The model builds on the concept of , an idea developed during the first decades of the 20th century. Plate tectonics came to be accepted by Earth science, geoscientists after seafloor spreading was validated in the mid-to-late 1960s. The processes that result in plates and shape Earth's crust are called ''tectonics''. Tectonic plates also occur in other planets and moons. Earth's lithosphere, the rigid outer shell of the planet including the crust (geology), crust and upper mantle, is fractured into seven or eight major plates (depending on how they are defined) and many minor plates or "platelets". Where the plates meet, their relative motion determines the type of plate boundary (or fault (geology), fault): , , or . The relative movement of the plates typically ranges from zero to 10 cm annu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cordilleras
A cordillera is a chain or network of mountain ranges, such as those in the west coast of the Americas. The term is borrowed from Spanish, where the word comes from , a diminutive of ('rope'). The term is most commonly used in physical geography p. 687 (Encyclopedia Americana Corp., 1918): "It is used particularly in physical geography, although in geology also it is sometimes applied...." and is particularly applied to the various large systems of the |
Longitudinal Valley
The Central Valley (), Intermediate Depression, or Longitudinal Valley is the depression between the Chilean Coastal Range and the Andes Mountains. The Chilean Central Valley extends from the border with Peru to Puerto Montt in southern Chile, with a notable interruption at Norte Chico (27°20'–33°00' S). South of Puerto Montt the valley has a continuation as a series of marine basins up to the isthmus of Ofqui. Some of Chile's most populous cities lie within the valley including Santiago, Temuco, Rancagua, Talca and Chillán. Northern section (18°30'–27°20' S) In northernmost Chile the central valley is made up of the Pampitas, a series of small flats dissected by deep valleys.Börger, p. 40. Immediately south of the Pampitas, in Tarapacá Region and northern of Antofagasta Region, the Central Valley is known as Pampa del Tamarugal.Börger, p. 41.Brüggen, p. 6. Contrary to the Pampitas valleys descending from the Andes do not incise the plains but merge into the surf ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
River
A river is a natural stream of fresh water that flows on land or inside Subterranean river, caves towards another body of water at a lower elevation, such as an ocean, lake, or another river. A river may run dry before reaching the end of its course if it runs out of water, or only flow during certain seasons. Rivers are regulated by the water cycle, the processes by which water moves around the Earth. Water first enters rivers through precipitation, whether from rainfall, the Runoff (hydrology), runoff of water down a slope, the melting of glaciers or snow, or seepage from aquifers beneath the surface of the Earth. Rivers flow in channeled watercourses and merge in confluences to form drainage basins, or catchments, areas where surface water eventually flows to a common outlet. Rivers have a great effect on the landscape around them. They may regularly overflow their Bank (geography), banks and flood the surrounding area, spreading nutrients to the surrounding area. Sedime ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
