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Ross Orogeny
The Ross orogeny was a mountain building event in Antarctica in the early Paleozoic. The ancestral (also termed proto-) Trans-Antarctic Mountains were uplifted earlier by the Beardmore orogeny but had eroded as a broad epicratonic sea flooded much of Antarctica in the Cambrian. Shallow water sedimentary rocks, platform carbonates and deepwater turbidites from this period are found in the mountain range. The Ross orogeny was one of the most extensive orogenic events in Antarctica, causing widespread plutonism and metamorphism. Bimodal magmatism and extension mark the beginnings of the orogeny, while during the later phase sedimentary rocks at the continental margin were deformed, metamorphosed and intruded with granite batholiths. Interpretations of rock forms in Antarctica during the 1980s suggested a westward-dipping subduction zone may have formed along the paleo-Pacific Ocean shoreline of East Antarctica. This is inferred from a large number of I-type and S-type granitoids whi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Orogeny
Orogeny is a mountain building process. An orogeny is an event that takes place at a convergent plate margin when plate motion compresses the margin. An ''orogenic belt'' or ''orogen'' develops as the compressed plate crumples and is uplifted to form one or more mountain ranges. This involves a series of geological processes collectively called orogenesis. These include both structural deformation of existing continental crust and the creation of new continental crust through volcanism. Magma rising in the orogen carries less dense material upwards while leaving more dense material behind, resulting in compositional differentiation of Earth's lithosphere ( crust and uppermost mantle). A synorogenic process or event is one that occurs during an orogeny. The word "orogeny" () comes from Ancient Greek (, , + , , ). Although it was used before him, the term was employed by the American geologist G. K. Gilbert in 1890 to describe the process of mountain-building as distinguished f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fold (geology)
In structural geology, a fold is a stack of originally planar surfaces, such as sedimentary strata, that are bent or curved during permanent 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''). Synsedimentary folds are those formed during sedimentary deposition. Folds form under varied conditions of stress, pore pressure, and temperature gradient, as evidenced by their presence in soft 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 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 fault (''fault bend fold''), at the tip of a propagating fault (''fault propagation fold''), by differential compaction or due to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geology Of Antarctica
The geology of Antarctica covers the geological development of the continent through the Archean, Proterozoic and Phanerozoic eons. The geological study of Antarctica has been greatly hindered by the fact that nearly all of the continent is continuously covered with a thick layer of ice. However, techniques such as remote sensing have begun to reveal the structures beneath the ice. Geologically, West Antarctica closely resembles the Andes of South America. The Antarctic Peninsula was formed by uplift and metamorphism of sea-bed sediments during the late Paleozoic and the early Mesozoic eras. This sediment uplift was accompanied by igneous intrusions and volcanism. The most common rocks in West Antarctica are andesite and rhyolite volcanics formed during the Jurassic Period. There is also evidence of volcanic activity, even after the ice sheet had formed, in Marie Byrd Land and Alexander Island. The only anomalous area of West Antarctica is the Ellsworth Mountains region, where ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
List Of Orogenies
The following is a list of known orogenies organised by continent, starting with the oldest at the top. The organization of this article is along present-day continents that do not necessarily reflect the geography contemporary to the orogenies. Note that some orogenies encompass more than one continent and might have different names in each continent. Likewise some very large orogenies include a number of sub-orogenies. As with other geological phenomena orogenies are often subject to different and changing interpretations regarding to their age, type and associated paleogeography. In some interpretations, especially in the older literature, the term orogeny is equivalent to a long "Episode" of basin formation and deposition of sediments (with durations of hundreds of millions of years), ending with deformation (sometimes including metamorphism) of these deposits. Some workers use the term only for the final mountain building deformation "Event" with a small duration of tens of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Queen Maud Mountains
The Queen Maud Mountains are a major group of mountains, ranges and subordinate features of the Transantarctic Mountains, lying between the Beardmore and Reedy Glaciers and including the area from the head of the Ross Ice Shelf to the Antarctic Plateau in Antarctica. Captain Roald Amundsen and his South Pole party ascended Axel Heiberg Glacier near the central part of this group in November 1911, naming these mountains for the Norwegian queen Maud of Wales. Despite the name, they are not located within Queen Maud Land. Elevations bordering the Beardmore Glacier, at the western extremity of these mountains, were observed by the British expeditions led by Ernest Shackleton (1907–09) and Robert Falcon Scott (1910-13), but the mountains as a whole were mapped by several American expeditions led by Richard Evelyn Byrd (1930s and 1940s), and United States Antarctic Program (USARP) and New Zealand Antarctic Research Program (NZARP) expeditions from the 1950s through the 1970s. Featu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Horlick Mountains
The Horlick Mountains are a mountain range in the Transantarctic Mountains of Antarctica. Some sources indicate that the designation includes the Ohio Range, the Long Hills, and all of the Wisconsin Range, while others suggest that it includes only the eastern portion of the Queen Maud Mountains and the main body of the Wisconsin Range. At one point the designation also included the Thiel Mountains. The mountains were discovered in two observations by the Byrd Antarctic Expedition, 1933–35, one by Kennett L. Rawson from a position in about , at the end of his southeastern flight of November 22, 1934, and another by Quin Blackburn in December 1934, from positions looking up Leverett and Albanus Glaciers. Portions of the Wisconsin Range are recorded in aerial photography obtained by USN Operation Highjump, 1946–47. The entire mountain group was surveyed by USARP parties and was mapped from U.S. Navy aerial photographs, 1959–64. Named by Admiral Richard E. Byrd for Will ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thiel Mountains
The Thiel Mountains are an isolated, mainly snow-capped mountain range of the Transantarctic Mountains System, located in the Ellsworth Land region of Antarctica. The mountain range is long, and is located roughly between the Horlick Mountains and the Pensacola Mountains, and extends from Moulton Escarpment on the west to Nolan Pillar on the east. Major components include Ford Massif (2,810 m), Bermel Escarpment and a group of eastern peaks near Nolan Pillar. The mountains were observed and first positioned by the USARP Horlick Mountains Traverse Party, 1958–59. The mountains were surveyed by the USGS Thiel Mountains parties of 1960-61 and 1961–62. The Thiel Mountains were named by US-ACAN after Dr. Edward C. Thiel, traverse seismologist at Ellsworth Station and the Pensacola Mountains in 1957. In December 1959, he made airlifted geophysical observations along the 88th meridian west, including work near these mountains. Thiel perished with four others on November 9 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pensacola Mountains
The Pensacola Mountains are a large group of mountain ranges of the Transantarctic Mountains System, located in the Queen Elizabeth Land region of Antarctica. Geography They extend 450 km (280 mi) in a NE-SW direction. Subranges of the Pensacola Mountains include: Argentina Range, Forrestal Range, Dufek Massif, Cordiner Peaks, Neptune Range, Patuxent Range, Rambo Nunataks and Pecora Escarpment. These mountain units lie astride the extensive Foundation Ice Stream and Support Force Glacier which drain northward to the Ronne Ice Shelf. ;Naming Discovered and photographed on 13 January 1956 in the course of a transcontinental nonstop plane flight by personnel of United States Navy Operation Deep Freeze I from McMurdo Sound to Weddell Sea and return. Named by US-ACAN for the U.S. Naval Air Station, Pensacola, Florida, in commemoration of the historic role of that establishment in training aviators of the U.S. Navy. The mountains were mapped in detail by USGS from surveys ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Shackleton Range
The Shackleton Range is a mountain range in Antarctica. Rising at Holmes Summit to , it extends in an east–west direction for about between the Slessor and Recovery glaciers. The range was named after Sir Ernest Shackleton, leader of the British Imperial Trans-Antarctic Expedition (or "Shackleton's Expedition") of 1914–16. Surveys The Commonwealth Trans-Antarctic Expedition (CTAE), which in 1956 saw the range from the air, conducted a ground-level survey of its western part in 1957. The United States Navy photographed the range from the air in 1967. In 1968–69 and 1969–70, the British Antarctic Survey (based at Halley Station) conducted further ground surveys with support from US Navy C-130 Hercules aircraft. Geology The Haskard Group and Turnpike Bluff Group rest unconformably on the Archean-Middle Proterozoic Shackleton Range Metamorphic Complex. The Ordovician-Early Devonian Blaiklock Glacier Group (475 Ma) also unconformably overlies the Shackleton Range Metam ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Intruded
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) an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Metamorphosed
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 distorti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Uplift Mountains
Orogeny is a mountain building process. An orogeny is an event that takes place at a convergent plate margin when plate motion compresses the margin. An ''orogenic belt'' or ''orogen'' develops as the compressed plate crumples and is uplifted to form one or more mountain ranges. This involves a series of geological processes collectively called orogenesis. These include both structural deformation of existing continental crust and the creation of new continental crust through volcanism. Magma rising in the orogen carries less dense material upwards while leaving more dense material behind, resulting in compositional differentiation of Earth's lithosphere ( crust and uppermost mantle). A synorogenic process or event is one that occurs during an orogeny. The word "orogeny" () comes from Ancient Greek (, , + , , ). Although it was used before him, the term was employed by the American geologist G. K. Gilbert in 1890 to describe the process of mountain-building as distinguished ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
