Misplaced Pages

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81-511: The Shackleton Range ( 80°30′S 25°00′W  /  80.500°S 25.000°W  / -80.500; -25.000 ) is a mountain range in Antarctica that rises to 1,875 metres (6,152 ft) and extends in an east–west direction for about 100 miles (160 km) between the Slessor and Recovery Glaciers. The Commonwealth Trans-Antarctic Expedition (CTAE), which in 1956 saw

162-654: A South African meteorologist with the CTAE. Not: Beney Nunataks. The Herbert Mountains ( 80°20′S 25°30′W  /  80.333°S 25.500°W  / -80.333; -25.500 ) are a conspicuous group of rock summits on the east side of Gordon Glacier in the Shackleton Range of Antarctica. They were first mapped in 1957 by the Commonwealth Trans-Antarctic Expedition and named for Sir Edwin S. Herbert , Chairman of

243-485: A long ice cap extending from the Fuchs Dome in the west to Shotton Snowfield in the east, and bounded by cliffs as high as 400 metres (1,300 ft). There are areas of rocky outcrop around the margins of the plateau. The Read Mountains on the southeast edge of the range are the highest, at 1,800 to 1,950 metres (5,910 to 6,400 ft), while there are lower peaks at 700 to 900 metres (2,300 to 3,000 ft) along

324-677: A massive dome of Proterozoic rock on the New York-Canada border. Both the Elzevirian (c. 1250–1190 Ma) and Ottawan (c. 1080–1020 Ma) orogenic pulses are recorded in the Adirondacks, producing high-grade metamorphic rock. A northwest-trending high-strain shear zone separates the dome into the highlands to the southeast and the lowlands to the northwest. It is believed that the shear zone (the Carthage-Colton)

405-843: A variety of rock types . Most geologically young mountain ranges on the Earth's land surface are associated with either the Pacific Ring of Fire or the Alpide belt . The Pacific Ring of Fire includes the Andes of South America, extends through the North American Cordillera , the Aleutian Range , on through Kamchatka Peninsula , Japan , Taiwan , the Philippines , Papua New Guinea , to New Zealand . The Andes

486-722: Is 7,000 kilometres (4,350 mi) long and is often considered the world's longest mountain system. The Alpide belt stretches 15,000 km across southern Eurasia , from Java in Maritime Southeast Asia to the Iberian Peninsula in Western Europe , including the ranges of the Himalayas , Karakoram , Hindu Kush , Alborz , Caucasus , and the Alps . The Himalayas contain the highest mountains in

567-528: Is a mountain massif with steep rock cliffs on its south side, rising to 1,850 metres (6,070 ft) in the south-central part of the Shackleton Range. It was first mapped in 1957 by the Commonwealth Trans-Antarctic Expedition , and it was photographed by U.S. Navy aircraft in 1967. It was named by the United Kingdom Antarctic Place-Names Committee (UK-APC) for Philip J. Stephenson, an Australian geologist with

648-501: Is a group of peaks and ridges extending northwest-southeast for 17 nautical miles (31 km; 20 mi) from Mount Lowe to Wyeth Heights , located west of Blaiklock Glacier and forming the west end of the Shackleton Range. Surveyed by the Commonwealth Trans-Antarctic Expedition in 1957. Named by the United Kingdom Antarctic Place-Names Committee (UK-APC) in 1972 after the De Havilland Otter aircraft which supported

729-765: Is a group of rocky summits, the highest Holmes Summit 1,875 metres (6,152 ft), lying east of Glen Glacier in the south-central part of the Shackleton Range. First mapped in 1957 by the Commonwealth Trans-Antarctic Expedition and named for Professor Herbert H. Read , Chairman of the Scientific Committee and member of the Committee of Management of the Commonwealth Trans-Antarctic Expedition, 1955–58. Stephenson Bastion ( 80°46′S 27°12′W  /  80.767°S 27.200°W  / -80.767; -27.200 )

810-495: Is a scattered group of nunataks extending west for 22 nautical miles (41 km) from the mouth of Gordon Glacier , on the north side of the Shackleton Range, Antarctica. They were first mapped in 1957 by the Commonwealth Trans-Antarctic Expedition (CTAE), and were photographed in 1967 by U.S. Navy aircraft. They were named by the UK Antarctic Place-Names Committee for Johannes J. La Grange,

891-538: Is at work while the mountains are being uplifted until the mountains are reduced to low hills and plains. The early Cenozoic uplift of the Rocky Mountains of Colorado provides an example. As the uplift was occurring some 10,000 feet (3,000 m) of mostly Mesozoic sedimentary strata were removed by erosion over the core of the mountain range and spread as sand and clays across the Great Plains to

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972-477: Is commonly of amphibolite and granulite facies , that is, medium to high temperature and pressure alteration. Eclogitized metagabbros (very high pressure ultramafic metamorphic rocks) are found in some localities and likely represent areas of deepest burial and/or most intense collision. Throughout the orogen, these sequences of high pressure metamorphic rocks are cut by intrusive AMCG suite plutons, generally interpreted as syn- or post-tectonic. AMCG plutonism

1053-532: Is composed of meta-igneous gneisses including anorthosite massifs. Anorthosites form in plutons and are composed mostly of plagioclase. The rocks of the Grenville Province in Canada are included in this category. The oldest magmatism known in this area dates to 1.32 Ga approximately. Granulite facies metamorphism began around 1.15 Ga and continued for about 150 Ma after the onset, however the continuity of

1134-512: Is constrained by cross-cutting relations observed in the field as well as SHRIMP ( sensitive high-resolution ion microprobe ) and TIMS ( thermal ionization mass spectrometry ) uranium-lead dating . The first period of tectonic activity was the accretion of an island arc at some point during the Elzevirian Orogeny. Before the accretion of the island arc took place, subduction between a continental plate and presumably an oceanic plate

1215-531: Is drier, having been stripped of much of its moisture. Often, a rain shadow will affect the leeward side of a range. As a consequence, large mountain ranges, such as the Andes, compartmentalize continents into distinct climate regions . Mountain ranges are constantly subjected to erosional forces which work to tear them down. The basins adjacent to an eroding mountain range are then filled with sediments that are buried and turned into sedimentary rock . Erosion

1296-430: Is generally associated with asthenospheric upwelling under thinned lithosphere . This is derived from the theory that AMCG plutonism is driven by ponding of olivine tholeiite basalt at the base of the continental crust during tectonic extension. The lithosphere may be thinned either convectively or by delamination , in which the bottom portion of the lithosphere is stripped off. Both models have been proposed for

1377-529: Is not the case. These periods of thrusting and metamorphism were not continuous but were interrupted by comparatively quiet periods, during which AMCG ( anorthosite / mangerite / charnockite / granite ) plutons were intruded into the country rock . Polarities of subduction (which plate overrode which) vary by region and time. Some island arc remnants were emplaced on the Laurentian margin, and some were accreted during orogeny. Timing of these events

1458-637: Is predominantly sedimentary and volcanic rocks which have undergone greenschist to granulite facies metamorphism. Subdivisions of this belt include the Bancroft, Elzevir, Sharbot Lake, and Frontenac Domains and the Adirondack Lowlands. In this belt magmatism is known to have occurred between 1.42 and 1.04 Ga depending on location. As with the Gneiss Belt, metamorphism is believed to have occurred at approximately 1.16 Ga. The Granulite Terrane

1539-603: Is suggested that the regime of subduction under the Laurentian margin (currently in Texas, north of the accreted Mexican terrane ) ended around 1230 Ma, and that subduction polarity reversed to bring the colliding continent north, since the Llano Uplift , which records the history of the Grenville in Texas, bears no evidence of arc magmatism after this time. The Appalachian Mountains contain small, isolated exposures of

1620-740: The Archean -Middle Proterozoic Shackleton Range Metamorphic Complex. The Ordovician -Early Devonian Blaiklock Glacier Group (475 Ma ) also unconformably overlies the Shackleton Range Metamorphic Complex. This group is composed of sandstones and conglomerates , and is unconformably overlain by the Beacon Supergroup . The range comprises three separate terranes with very different histories. Analysis of geochronological data in these terranes implies that East Antarctica finally came together during

1701-413: The Commonwealth Trans-Antarctic Expedition (CTAE) and named for Sir Vivian E. Fuchs , leader of the CTAE 1955–58. 80°35′S 23°15′W  /  80.583°S 23.250°W  / -80.583; -23.250 . A large snowfield between Herbert Mountains and Pioneers Escarpment on the north and Read Mountains on the south, in the Shackleton Range. The U.S. Navy obtained aerial photographs of

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1782-580: The Commonwealth Trans-Antarctic Expedition , and photographed from the air by the U.S. Navy in 1967. They were surveyed by the British Antarctic Survey between 1968 and 1971, and named by the UK Antarctic Place-Names Committee in 1971 after Sir Cosmo Haskard , Governor of the Falkland Islands 1964–70. La Grange Nunataks ( 80°18′S 27°50′W  /  80.300°S 27.833°W  / -80.300; -27.833 )

1863-642: The Filchner Ice Shelf to the north of the Shackleton Range. First seen from the air and mapped by the CTAE in 1956. Named by the CTAE for Marshal of the RAF Sir John Slessor , chairman of the expedition committee. Glacier ( 80°44′S 25°16′W  /  80.733°S 25.267°W  / -80.733; -25.267 ) at least 7 miles (11 km) long, flowing south in the Shackleton Range to join Recovery Glacier to

1944-577: The Mithrim Montes and Doom Mons on Titan, and Tenzing Montes and Hillary Montes on Pluto. Some terrestrial planets other than Earth also exhibit rocky mountain ranges, such as Maxwell Montes on Venus taller than any on Earth and Tartarus Montes on Mars . Jupiter's moon Io has mountain ranges formed from tectonic processes including the Boösaule , Dorian, Hi'iaka and Euboea Montes . Grenville orogeny The Grenville orogeny

2025-473: The Ocean Ridge forms the longest continuous mountain system on Earth, with a length of 65,000 kilometres (40,400 mi). The position of mountain ranges influences climate, such as rain or snow. When air masses move up and over mountains, the air cools, producing orographic precipitation (rain or snow). As the air descends on the leeward side, it warms again (following the adiabatic lapse rate ) and

2106-687: The Paleoproterozoic was very similar to that of the Mawson Continent , which may mean that this continent extends over the Eastern Antarctic Shield and includes the Shackleton Range. The Eastern Terrane holds granitoid rocks formed around 1,060 million years ago during the Grenville orogeny that experienced metamorphism around 600 million years ago. The events at 1,060 and 600 million years ago are similar to

2187-672: The Pan-African orogeny , and its components were separate earlier in the Mesoproterozoic . The southern belt, exposed in the Read Mountains , has medium- to high-grade metamorphic rocks classified as the Read Group. They are mainly composed of partly migmatised quartzitic, basic, calcareous and pelitic rocks. In places they are interlayered with gneissic granites, and intruded by granites and basic rocks. Dating of

2268-724: The Sør Rondane Mountains and the Lützow-Holm Bay area to the north. The Shackleton Range is 170 kilometres (110 mi) long in an east-west direction and up to 70 kilometres (43 mi) wide. It stretches from the Filchner Ice Shelf eastward until it is fully covered at a height of about 2,000 metres (6,600 ft) by the Antarctic ice sheet. The range is an ice-covered plateau between 1,200 and 1,600 metres (3,900 and 5,200 ft) high that rises between two large glaciers. The plateau generally slopes down to

2349-803: The Whichaway Nunataks and the Pensacola Mountains around the end of the Miocene during the last major expansion of the Antarctic ice sheet. The ice was 1,000 metres (3,300 ft) thicker than today, and the ice flowed north unaffected by the local landforms. During the Last Glacial Period , the Filchner ice shelf expanded and blocked the Slessor Glacier, which deposited till and scattered erratics. Today,

2430-441: The magmatic activity associated with the individual cycles of the orogeny. The gaps in the ages of the compression cycles and isotope analysis of hornblende , biotite , and potassium feldspar suggest that extension was occurring when compression had momentarily ceased. Rivers' 2008 paper examines the timing of the different periods of the orogeny and reconstructs the timeline based on the spatial and temporal metamorphism of

2511-443: The CTAE and named for Gen. Sir James H. Marshall-Cornwall , member of the Committee of Management of the CTAE, 1955-58. 80°18′S 25°05′W  /  80.300°S 25.083°W  / -80.300; -25.083 . A glacier in the east part of Herbert Mountains, Shackleton Range, flowing north-northeast into Slessor Glacier . Photographed from the air by the U.S. Navy, 1967, and surveyed by BAS, 1968-71. In association with

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2592-423: The CTAE and so named because this pass, together with Gordon and Cornwall Glaciers, provides a sledging route across the Shackleton Range from north to south. 80°28′S 28°20′W  /  80.467°S 28.333°W  / -80.467; -28.333 . A snow pass at c. 1,000 metres (3,300 ft) trending east-west between the northwest side of Fuchs Dome and Flat Top in the Shackleton Range. The area

2673-445: The CTAE. The Haskard Highlands ( 80°30′S 29°15′W  /  80.500°S 29.250°W  / -80.500; -29.250 ) are a range of peaks and ridges between Blaiklock Glacier and Stratton Glacier in the northwest of the Shackleton Range, Antarctica, rising to 1,210 metres (3,970 ft) at Mount Weston and including features between Mount Provender and Pointer Nunatak . The highlands were first mapped in 1957 by

2754-416: The Filchner ice shelf. This results in rapid flow, with areas of chaotic ice and many crevasses. The Recovery Glacier is about 80 kilometres (50 mi) wide, and drops from about 1,200 to 800 metres (3,900 to 2,600 ft) along the range. With a lower gradient it flows more slowly and has fewer crevasses. The Schimper Glacier , Gordon Glacier , Stratton Glacier and Blaiklock Glacier flow northwest from

2835-496: The Finance Committee and a Member of the Committee of Management of the expedition, 1955–58. Pioneers Escarpment ( 80°28′S 21°7′W  /  80.467°S 21.117°W  / -80.467; -21.117 ) is a mostly snow-covered north-facing escarpment, interrupted by occasional bluffs and spurs, between Slessor Glacier on the north and Shotton Snowfield on the south, in the Shackleton Range. The escarpment

2916-525: The Fuchs Dome and Shotton Snowfield and the table mountains that surround them are the remnants of the peneplain . In the Read Mountains there are south-facing cirques as wide as 7 kilometres (4.3 mi) surrounded by high cliffs. The ridges between the cirques stretch over 10 kilometres (6.2 mi) to the south, and in seven cases widen to form flat-topped buttes. In the north and northwest

2997-547: The Grenville Province prior to opening of the Iapetus Ocean, the two share largely the same history. Texas and Mexico represent the southern margin of Laurentia and likely collided with a different continent than that involved in the eastern collision. The Zapotecan orogeny of Mexico is coeval with the later stages of the Grenville orogeny, and they are generally considered to be one and the same. Mesoproterozoic igneous protoliths (metamorphosed to granulite facies during

3078-526: The Grenville orogen. The Andes of South America are considered a modern analogue. From about c. 1190–980 Ma (the actual timing varies by locality) two separate continental blocks collided with Laurentia. Both of these collision events are thought to be analogous to the collision driving modern-day growth of the Himalaya range. For some time one of the blocks was believed to be the continent of Amazonia, but paleomagnetic evidence has now proven that this

3159-834: The Grenville orogen. The largest of these, the Long Range Inlier, comprises the Long Range Mountains of Newfoundland. Other exposures include the Shenandoah and French Broad massifs , which comprise the Blue Ridge province of Virginia. Blue Ridge rocks consist of various gneisses of upper amphibolite and granulite facies, intruded by charnockite and granitoid rocks. These igneous rocks were intruded in three intervals: c. 1160–1140  Ma, c. 1112 Ma, and c. 1080–1050 Ma, and are massive to weakly foliated in texture. This region consists of

3240-496: The Grenville orogeny. The Grenville orogeny can be categorized into three sections based on structure, lithology, and thermochronology. The three sections, respectively called the Gneiss Belt, Metasedimentary Belt, and the Granulite terrane are all separated by shear zones. The Gneiss Belt is made up of felsic gneisses and amphibolites that were metamorphosed in the upper amphibolite to granulite facies. Thrusting in this section

3321-745: The Grenvillian and Pan-African tectonics in Queen Maud Land , suggesting that the Shackleton Range holds part of the Pan African Mozambique/Maud Belt . The suture located in the extreme east of the range was formed during the amalgamation of West Gondwana and the Indo-Antarctic plate . The northern belt extends from the Pioneer Escarpment in the east to the northern Haskard Highlands in

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3402-712: The Pan-African Ross Orogony along the former Pacific edge of the East Antarctic Craton. The two ranges differ in structural trends, being almost at right angles to each, and in rock types. It is commonly thought that the Shackleton Range was caused by an oblique collision between the East Antarctic and Kalahari cratons that closed the Mozambique Ocean . The Haskard Group and Turnpike Bluff Group rest unconformably on

3483-493: The Shackleton Range to join Slessor Glacier . First mapped in 1957 by the CTAE and named after George P. Pirie-Gordon, member of the Committee of Management and treasurer of the CTAE, 1955-58. 80°22′S 29°00′W  /  80.367°S 29.000°W  / -80.367; -29.000 . A glacier 20 miles (32 km) long, flowing north from Pointer Nunatak and then northwest to the north of Mount Weston , in

3564-409: The Shackleton Range. First mapped in 1957 by the CTAE and named for David G. Stratton, surveyor and deputy leader of the transpolar party of the CTAE in 1956-58. 80°30′S 29°51′W  /  80.500°S 29.850°W  / -80.500; -29.850 . Glacier 16 miles (26 km) long, flowing north from Turnpike Bluff , then northwest to Mounts Provender and Lowe in the west part of

3645-410: The Shackleton Range. First mapped in 1957 by the CTAE and named for Kenneth V. Blaiklock, leader of the advance party of the CTAE in 1955-56 and surveyor with the transpolar party in 1956-58. 80°38′S 26°30′W  /  80.633°S 26.500°W  / -80.633; -26.500 . Pass between Gordon and Cornwall Glaciers in the central part of the Shackleton Range. First mapped in 1957 by

3726-536: The compressional activity in the area reactivated some extensional faults. The extension is marked by the isotopic ages of the previously mentioned rocks. Additionally there is the formation of sedimentary basins which means the margin was quiescent enough that sediments could accumulate. However, in some areas from 1.16 to 1.13 Ga, coeval with extension, there is evidence there was still thrusting and emplacement of terranes occurring. According to one model, westward thrusting occurred from 1.12 to 1.09 Ga and then extension

3807-485: The east. This mass of rock was removed as the range was actively undergoing uplift. The removal of such a mass from the core of the range most likely caused further uplift as the region adjusted isostatically in response to the removed weight. Rivers are traditionally believed to be the principal cause of mountain range erosion, by cutting into bedrock and transporting sediment. Computer simulation has shown that as mountain belts change from tectonically active to inactive,

3888-434: The events of the orogeny is ongoing, but the generally accepted view is that the eastern and southern margins of Laurentia were active convergent margins until the beginning of continental collision . This type of subduction (B-type) tends to emplace magmatic arcs on or near the edge of the overriding plate in modern subduction zones, and evidence of contemporary (c. 1300–1200 Ma) island arcs can be found throughout

3969-590: The fact that our planet is dynamic. The cyclic compression and extension history of this area is similar to the Wilson Cycle . In this area of the world the Wilson Cycle would be creating the basin for the Iapetus Ocean . Today, the Grenville orogen is marked by northwest verging fold-and-thrust belts and high pressure metamorphic regimes, as well as distinctive AMCG suite magmatism. Metamorphism

4050-480: The feature in 1967 and it was surveyed by BAS, 1968-71. Named by the UK-APC, 1971, in association with the names of glacial geologists grouped in this area, after Frederick W. Shotton (1906-90), British Quaternary geologist and Professor of Geology, University of Birmingham, 1949-74. Not: Shottonfonna. Otter Highlands ( 80°38′S 30°0′W  /  80.633°S 30.000°W  / -80.633; -30.000 )

4131-476: The generic name of the freshwater alga found growing in the lake. Mountain range Mountain ranges are usually segmented by highlands or mountain passes and valleys . Individual mountains within the same mountain range do not necessarily have the same geologic structure or petrology . They may be a mix of different orogenic expressions and terranes , for example thrust sheets , uplifted blocks , fold mountains, and volcanic landforms resulting in

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4212-523: The ground by the CTAF in 1957, and so named because of the recovery of the expedition's vehicles which repeatedly broke into bridged crevasses on this glacier during the early stages of the crossing of Antarctica. Not: Glaciar Expedicion Polar Argentina, Glaciar Falucho. 79°50′S 28°30′W  /  79.833°S 28.500°W  / -79.833; -28.500 . Glacier at least 75 miles (121 km) long and 50 miles (80 km) wide, flowing west into

4293-600: The ice in most of the range still flows north into the Slessor Glacier. However, ice from a small area in the southwest of the snowfield flows south between the Read Mountains and the Stephenson Bastion into the Recovery Glacier, and small glaciers carry ice south from the Read Mountains and Stephenson Bastion. The high table mountains in the south, exposed to the prevailing winds, have been free of ice for longest and have experienced more weathering than

4374-591: The interior of the range the Fuchs Dome is in the west part, from which the Shotton Snowfield extends to the east. The Otter Highlands are at the west end of the range between the Slessor and Recovery glaciers. Extending eastward along the north (Slessor) side of the range are the Haskard Highlands , La Grange Nunataks , Herbert Mountains and Pioneers Escarpment . From east to west along

4455-488: The lower mountains to the north. The Read Mountains have probably been ice-free since before the Quaternary . With few exceptions the table top mountains are free of glacial deposits, although glacial striations and crescentic gouges show that they have been subject to glacial activity in the past. The assumption is that during the long ice-free period the deposits have been eroded away. Download coordinates as: In

4536-420: The metagranites gives ages of around 1,760 and 1,600 million years. Rb–Sr and K-Ar mineral cooling ages are 1650–1550 million years. The Southern Terrane has detritus up to 2,850 million years old that experienced magmatism from 1,850 to 1,810 million years ago, a metamorphic event between 1,710 and 1,680 years ago, and another metamorphic event 510 million years ago. Tectonics in the Southern Terrane during

4617-447: The metamorphism cannot be determined. It is important to separate local from large-scale tectonic history of the orogenic belt in order to understand the orogeny. For this purpose, the Grenville orogen is generally broken into four localities: the southern extent in Texas and Mexico, the Appalachians , the Adirondacks , and the Grenville Province . A portion of the orogen can be found in Scotland, but because of Scotland's proximity to

4698-423: The most detailed records of the orogeny. This classification considers the classical Grenville designation to cover two separate orogenic cycles; the Rigolet, Ottawan and Shawingian orogenies compose the Grenville Cycle, and the Elzevirian orogeny stands on its own. Due to the great size of the area affected by Grenville events, there is some variance in timing across the orogenic belt . Ages are approximated from

4779-437: The names of glacial geologists grouped in the area, named by the UK-APC after Karl Friedrich Schimper (1803–67), German botanist who in 1835 originated the theory of the Ice Age in Europe to account for the distribution of erratic boulders. 80°17′S 26°09′W  /  80.283°S 26.150°W  / -80.283; -26.150 . Glacier at least 24 miles (39 km) long, flowing north from Crossover Pass through

4860-407: The north, so most of the ice from the range flows via wide glaciers into the fast-moving Slessor Glacier, and much less flows south into the slower-moving Recovery Glacier. This probably explains why erosion is higher in the north of the range. The Shackleton Range is a rectangular horst rising above major fault zones now under the Slessor and Recovery glaciers. The center of the range is covered by

4941-408: The northern edge. The connected valleys of the north-flowing Gordon Glacier and south-flowing Cornwall Glacier may reflect an underlying fault zone, and have been treated as a divide between the western and eastern portions of the Shackleton Range. The plateau surface is a discontinuous and faulted undulating peneplain , most visible on the south of the range. The flat areas free of ice at the edge of

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5022-405: The orogeny) fall into two age groups in Mexico; c. 1235–1115 Ma and c. 1035–1010 Ma. Rocks of the former group bear geochemical signatures implying island arc and back-arc basin provenance. The latter group represents AMCG magmatism. These AMCG rocks are somewhat anomalous throughout the Grenville orogen, there is no known orogenic event which immediately predates their emplacement. It

5103-493: 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. The range was named after Sir Ernest Shackleton (1874–1922), leader of the British Imperial Trans-Antarctic Expedition (or "Shackleton's Expedition") of 1914–1916,

5184-412: The range into the Slessor Glacier. The Glen Glacier and Cornwall Glacier flow south into the Recovery Glacier. 81°10′S 28°00′W  /  81.167°S 28.000°W  / -81.167; -28.000 . Glacier, at least 60 miles (97 km) long and 40 miles (64 km) wide at its mouth, flowing west along the south side of the Shackleton Range. First seen from the air and examined from

5265-414: The range is made up of small table mountains and isolated peaks. There are fifteen table mountains in the south of the range, seven in the southwest and just three in the north. The geology and origin of glacial erratics , and the evidence of subglacial erosion in the Shackleton Range show that the whole range was once overrun by ice from the south or southeast. The erratics were probably carried north from

5346-516: The rate of erosion drops because there are fewer abrasive particles in the water and fewer landslides. Mountains on other planets and natural satellites of the Solar System, including the Moon , are often isolated and formed mainly by processes such as impacts, though there are examples of mountain ranges (or "Montes") somewhat similar to those on Earth. Saturn 's moon Titan and Pluto , in particular, exhibit large mountain ranges in chains composed mainly of ices rather than rock. Examples include

5427-415: The rocks present. According to this newer version of the timeline which is a composite of Rivers 1997 and Gower and Krogh 2002, the Elzevirian orogeny occurs from 1240 to 1220 Ma, the Shawinigan occurs from 1190 to 1140 Ma and is no longer part of the Grenville cycle, the Ottawan (now 1090–1020 Ma) and Rigolet (still 1010–980 Ma) become phases which are grouped into the Grenvillian orogeny. Reconstruction of

5508-411: The south (Recovery) side of the range are the Read Mountains and Stephenson Bastion . Fuchs Dome ( 80°36′S 27°50′W  /  80.600°S 27.833°W  / -80.600; -27.833 ) is a large ice-covered dome rising over 1,525 metres (5,000 ft), between Stratton Glacier and Gordon Glacier in the central part of the Shackleton Range, Antarctica. It was first mapped in 1957 by

5589-417: The southern and eastern margins of Laurentia are recognized under the "Grenville" name. These orogenic events are also known as the Kibaran orogeny in Africa and the Dalslandian orogeny in Western Europe . The problem of timing the Grenville orogeny is an area of some contention. The timescale outlined by Toby Rivers in 2002 is derived from the well-preserved Grenville Province and represents one of

5670-427: The transpolar party of the CTAE in 1956–58. The range lies between the Slessor Glacier to the north and the Recovery Glacier to the south, both of which flow west into the Filchner–Ronne Ice Shelf . Slessor Glacier is about 50 kilometres (31 mi) wide and drops from an elevation of over 800 metres (2,600 ft) at the eastern end of the range to about 200 metres (660 ft) at the western end where it enters

5751-416: The unsuccessful forerunner of the Commonwealth Trans-Antarctic Expedition (CTAE). Unofficial names include Cordillera Los Menucos, Cordon Los Menucos, Shackletonkjeda, Shackleton Mountains. The range is at the northwestern edge of the East Antarctic Craton . To the west of the Shackleton Range, the Transantarctic Mountains run from north to south. These mountains formed around 500 million years ago during

5832-428: The west of Read Mountains. First mapped in 1957 by the CTAE and named for Alexander R. Glen, member of the Committee of Management of the CTAE, 1955–58. 80°47′S 26°16′W  /  80.783°S 26.267°W  / -80.783; -26.267 . Glacier 9 miles (14 km) long, flowing south from Crossover Pass in the Shackleton Range to join Recovery Glacier east of Ram Bow Bluff . First mapped in 1957 by

5913-719: The west. It has been divided into the Pioneers Group, the Stratton Group, and an ophiolite complex that may be a relic of the Mozambique Ocean. The Northern Terrane has paragneisses , mafic and ultramafic rocks that host granites and diorites dating to 530 million years ago, which experienced metamorphism 510 to 500 million years ago. This terrane holds the suture formed when the combined Indo-Antarctic/West Gondwanan block collided with East Gondwana about 510 million years ago. The suture may also extend through

5994-543: The world, including Mount Everest , which is 8,848 metres (29,029 ft) high. Mountain ranges outside these two systems include the Arctic Cordillera , Appalachians , Great Dividing Range , East Siberians , Altais , Scandinavians , Qinling , Western Ghats , Vindhyas , Byrrangas , and the Annamite Range . If the definition of a mountain range is stretched to include underwater mountains, then

6075-493: Was a long-lived Mesoproterozoic mountain-building event associated with the assembly of the supercontinent Rodinia . Its record is a prominent orogenic belt which spans a significant portion of the North American continent, from Labrador to Mexico , as well as to Scotland . Grenville orogenic crust of mid-late Mesoproterozoic age ( c. 1250—980 Ma ) is found worldwide, but generally only events which occurred on

6156-536: Was a transpressional boundary during the Ottawan, when the highlands were thrust over the lowlands. The Grenville province is named for Grenville , Quebec, and constitutes the youngest portion of the Canadian Shield . Since the area has not undergone any regional metamorphic overprinting since the orogeny, it is considered an ideal study area for Grenville and pre-Grenville age tectonics. Hence, most of what

6237-469: Was low angle but would have the potential to increase and rotate as it continued and evolved. Shear in this area is referred to as ductile shear meaning the material was cooling and becoming solid, but still behaving viscously or plasticly. The age of this belt is approximately 1.8 to 1.18 Ga. Regional metamorphism is believed to have deformed this area at approximately 1.4 Ga and metamorphic thrusting at approximately 1.16 to 1.12 Ga. The Metasedimentary Belt

6318-450: Was photographed from the air by the U.S. Navy , 1967, and was surveyed by British Antarctic Survey (BAS), 1968–71. So named by United Kingdom Antarctic Place-Names Committee (UK-APC) because features on the escarpment are named after the pioneers whose inventions have assisted living and traveling conditions in the polar regions. Read Mountains' 80°42′S 24°45′W  /  80.700°S 24.750°W  / -80.700; -24.750

6399-399: Was surveyed by CTAE in 1957. Named by the UK-APC after Michael A. Warden, BAS general assistant, Halley Station, 1970-72, who worked in the area. 80°24′S 30°05′W  /  80.400°S 30.083°W  / -80.400; -30.083 Lake lying 1 mile (1.6 km) southwest of Mount Provender in the west part of the Shackleton Range. First mapped in 1957 by the CTAE and given

6480-520: Was taking place. Slab pull and far-field drivers such as ridge push were aiding in closing the distance between the island arc and the continent. Depending on the angle of subduction, deformation of the continental crust was already taking place and thickening the lithosphere . By 1.19 Ga the Elzevir back arc basin was closing. From 1.18 to 1.14 Ga extension was occurring in the area. Whether from lithospheric cooling, also known as thermal subsidence, or

6561-525: Was the primary tectonic activity until 1.05 Ga. It was at this point that the Central Granulite Terrane was exhumed and minor magmatism occurred. The reason for change from compression to extension is unknown but may be the result of gravitational collapse, mantle delamination, the formation of a plume underneath a supercontinent , changes in far-field drivers on the distribution of stress, or any combination of reasons originating from

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