"Pingo A pingo, also called a hydrolaccolith or a bulgunniakh, is a mound of earth-covered ice found in the Arctic and subarctic that can reach up to in height and up to in diameter. The term originated as the Inuvialuktun word for a small hill. The plural form is ""pingos"". The term is also used for depressions, often water filled, formed by the melting of ice at the end of the last glaciation. A pingo is a periglacial landform, which is defined as a nonglacial landform or process linked to colder climates. ""Periglacial"" suggests an environment located on the margin"
"the core mound of igneous rock. The term was first applied as laccolite by Grove Karl Gilbert after his study of intrusions of diorite in the Henry Mountains of Utah in about 1875. The filled and solidified magma chamber of Torres del Paine (Patagonia) is one of the best exposed laccoliths, built up incrementally by horizontal granitic and mafic magma intrusions over 162 ± 11 thousand years. Horizontal sheeted intrusions were fed by vertical intrusions. It is often difficult to reconstruct shapes of intrusions. For instance, Devils Tower in Wyoming was thought to be a volcanic neck, but study has"
"Phacolith A phacolith is a pluton of igneous rock parallel to the bedding plane or foliation of folded country rock. More specifically, it is a typically lens-shaped pluton that occupies either the crest of an anticline or the trough of a syncline. In rare cases the body may extend as a sill from the crest of an anticline through the trough of an adjacent syncline, such that in cross section it has an ""S"" shape. In intensely folded terrain the hinge of folds would be areas of reduced pressure and thus potential sites for magma migration and emplacement. The term"
"as high as 60 metres, known as pingos, which are fed by an upwelling of ground water, instead of the capillary action that feeds the growth of frost heaves. Cryogenic earth hummocks are a small formation resulting from granular convection that appear in seasonally frozen ground and have many different names; in North America they are earth hummocks; thúfur in Greenland and Iceland; and pounus in Fennoscandia. Polygonal forms apparently caused by frost heave have been observed in near-polar regions of Mars by the Mars Orbiter Camera (MOC) aboard the Mars Global Surveyor and the HiRISE camera on the Mars"
"Hummock A hummock is a small knoll or mound above ground. They are typically less than 15 meters in height and tend to appear in groups or fields. It is difficult to make generalizations about hummocks because of the diversity in their morphology and sedimentology. An extremely irregular surface may be called ""hummocky"". An ice hummock is a boss or rounded knoll of ice rising above the general level of an ice-field. Hummocky ice is caused by slow and unequal pressure in the main body of the packed ice, and by unequal structure and temperature at a later period. Hummocks"
"turbulent moving mass. Hummock A hummock is a small knoll or mound above ground. They are typically less than 15 meters in height and tend to appear in groups or fields. It is difficult to make generalizations about hummocks because of the diversity in their morphology and sedimentology. An extremely irregular surface may be called ""hummocky"". An ice hummock is a boss or rounded knoll of ice rising above the general level of an ice-field. Hummocky ice is caused by slow and unequal pressure in the main body of the packed ice, and by unequal structure and temperature at a"
"°C. A high-latitude region covered in ice, though strictly not an ice cap (since they exceed the maximum area specified in the definition above), are called polar ice caps; the usage of this designation is widespread in the mass media and arguably recognized by experts. Vatnajökull is an example of an ice cap in Iceland. Ice cap An ice cap is a mass of ice that covers less than 50,000 km of land area (usually covering a highland area). Larger ice masses covering more than 50,000 km are termed ice sheets. Ice caps are not constrained by topographical features (i.e.,"
"Laccolith A laccolith is a sheet intrusion (or concordant pluton) that has been injected between two layers of sedimentary rock. The pressure of the magma is high enough that the overlying strata are forced upward, giving the laccolith a dome or mushroom-like form with a generally planar base. Laccoliths tend to form at relatively shallow depths and are typically formed by relatively viscous magmas, such as those that crystallize to diorite, granodiorite, and granite. Cooling underground takes place slowly, giving time for larger crystals to form in the cooling magma. The surface rock above laccoliths often erodes away completely, leaving"
"much slower rate and at a lower level. The Shonkin Sag lends its name to the Shonkin Sag laccolith, a famous laccolith thick and wide near the western mouth of the Shonkin Sag. A laccolith is an igneous intrusion injected between two layers of sedimentary rock. Significant amounts of syenite and shonkinite can be found in the laccolith. The Shonkin Sag laccolith is cited by geologists as a classic example of igneous differentiation in a single igneous intrusion. Part of the North Montana line of the Chicago, Milwaukee, St. Paul and Pacific Railroad was constructed within Shonkin Sag (see photo"
"is extremely sparse. The glacier is featured in the final scene of the 1999 animated film ""The Iron Giant"", directed by Brad Bird. Langjökull Langjökull (Icelandic for ""long glacier"") is the second largest ice cap in Iceland (953 km), after Vatnajökull. It is situated in the west of the Icelandic interior or Highlands of Iceland and can be seen clearly from Haukadalur. The glacier is located at . Its volume is 195 km³ and the ice is up to thick. The highest point of the ice cap (at Baldjökull at the northern end of Langjökull) is about above sea level."
"altitude of . The lake is dammed by a high unconsolidated terminal moraine dam. The lake is growing larger every year due to the melting and retreat of the Trakarding Glacier, and has become the largest and most dangerous glacier lake in Nepal, with approximately 90 to 100 million m (117 to 130 million yd) of water stored. The most famous are the immense jökulhlaup released from the Vatnajökull Ice Cap in Iceland. It is not by chance that the term ""jökulhlaup"" (""jökull"" = glacier, ""hlaup"" = run (""n."")/running) comes from Icelandic, as the south of Iceland has very often"
"and ice sheets. Because they are typically isolated from the main mountains, they are often easier to access. Nunataks were first described in Greenland. Nunatak means ""lonely peak"" in Inuktitut. Due to their sterile surroundings and isolation, nunataks are rarely or never visited. The land area on and surrounding Mericle Rock is not cultivated. The vegetation natural to the area is mainly still intact. Mericle Rock is a Summit. The estimated terrain elevation above sea level of Mericle Rock is 1,836 meters (6,023 feet, 7 15/32 inches). Antarctica is Earth's highest continent. The average elevation is 2,500 meters (8,200 feet)."
"site of ""Boscoia sudpolaris"". Mount Harcourt Mount Harcourt, also known as Mount Vernon Harcourt, is a stratovolcano (1,570 m) making up part of the Hallett Peninsula, Victoria Land, Antarctica, extending into the Ross Sea about south of Mount Erebus, along with three overlapping shield volcanoes. It was discovered in January 1841 by Sir James Clark Ross and named by him for the Reverend William Vernon Harcourt, one of the founders of the British Association. Two dates have been obtained from the volcano's rock, roughly 5.5 and 6.6 million years in age. These samples are alkalic in composition. The volcano is"
"within and totally covered by the ice shelf may appear the same as an ice rise. Elaborate measurements may be required to distinguish between these two geographic features. Although ice rises are typically located within the ice shelf area, they can partially face the open sea. Ice rises are found only on the ice shelves of Antarctica. The largest ice rises exceed dimensions of 50 by 200 km, or 10 000 km² in area. Some ice rises are incorrectly called islands, but also a few totally ice-covered islands within an ice shelf are also called ice rises. Ice rises, grouped"
"Batholith A batholith (from Greek ""bathos"", depth + ""lithos"", rock) is a large mass of intrusive igneous rock (also called plutonic rock), larger than in area, that forms from cooled magma deep in the Earth's crust. Batholiths are almost always made mostly of felsic or intermediate rock types, such as granite, quartz monzonite, or diorite (see also ""granite dome""). Although they may appear uniform, batholiths are in fact structures with complex histories and compositions. They are composed of multiple masses, or ""plutons"", bodies of igneous rock of irregular dimensions (typically at least several kilometers) that can be distinguished from adjacent"
"Thermokarst Thermokarst is a land surface characterised by very irregular surfaces of marshy hollows and small hummocks formed as ice-rich permafrost thaws, that occurs in Arctic areas, and on a smaller scale in mountainous areas such as the Himalayas and the Swiss Alps. These pitted surfaces resemble those formed by solution in some karst areas of limestone, which is how they came to have karst attached to their name without the presence of any limestone. Small domes that form on the surface due to frost heaving with the onset of winter are only temporary features. They then collapse with the"
"areas less than 50,000 square kilometers, while ice sheets span larger areas. Ice sheets and ice caps can be classified further. An ice dome is an upstanding ice surface located in the accumulation zone of the higher altitude portions of an ice cap or ice sheet. Ice domes are nearly symmetrical with a convex or parabolic surface shape. They tend to develop evenly over a land mass that may be either a topographic height or a depression—often reflecting the sub-glacial topography. In ice sheets, domes may reach a thickness that may exceed 3,000 m, but in ice caps the thickness"
"Antarctica. It has an area of . The island is almost entirely covered by glacier, with about 95% of the surface covered by ice. Surrounding the island is a tall ice front and vertical cliffs. The long stretches of ice caps are supplemented with rock outcrops. Landing is only possible at three points, and only during the short period of the year in which the island is not surrounded by pack ice. The island is a shield volcano, although it is not known if it is still active. An ultra prominent peak at elevation, it is named for Lars Christensen."
"surface of the Moon. These igneous features may be confused with impact cratering. Laccolith A laccolith is a sheet intrusion (or concordant pluton) that has been injected between two layers of sedimentary rock. The pressure of the magma is high enough that the overlying strata are forced upward, giving the laccolith a dome or mushroom-like form with a generally planar base. Laccoliths tend to form at relatively shallow depths and are typically formed by relatively viscous magmas, such as those that crystallize to diorite, granodiorite, and granite. Cooling underground takes place slowly, giving time for larger crystals to form in"
"""valley glacier"", or alternatively an ""alpine glacier"" or ""mountain glacier"". A large body of glacial ice astride a mountain, mountain range, or volcano is termed an ""ice cap"" or ""ice field"". Ice caps have an area less than by definition. Glacial bodies larger than are called ""ice sheets"" or ""continental glaciers"". Several kilometers deep, they obscure the underlying topography. Only nunataks protrude from their surfaces. The only extant ice sheets are the two that cover most of Antarctica and Greenland. They contain vast quantities of fresh water, enough that if both melted, global sea levels would rise by over ."
"was coined and initially defined by Alfred Harker in his ""The Natural History of Igneous Rocks"" in 1909. Phacolith A phacolith is a pluton of igneous rock parallel to the bedding plane or foliation of folded country rock. More specifically, it is a typically lens-shaped pluton that occupies either the crest of an anticline or the trough of a syncline. In rare cases the body may extend as a sill from the crest of an anticline through the trough of an adjacent syncline, such that in cross section it has an ""S"" shape. In intensely folded terrain the hinge of"
"found in Parc National des Ecrins, France. Additional research has found them to be hydrothermally altered basalt volcanic rocks that contain amygdules filled with white calcite and other secondary minerals. Variolite Variolites are mafic, igneous, and typically volcanic rocks, e.g. tholeiite, basalt or komatiite, that contain centimeter-scale spherical or globular structures, called ""varioles"", in a fine-grained matrix. These structures are lighter colored than the host rock and typically range in diameter from 0.05mm to over 5 cm. In 1648, Aldrovandi created the term ""variolite"" for aphanitic or fine-grained igneous rocks containing varioles. The weathering of varioles often cause variolites to"
"Mount Harcourt Mount Harcourt, also known as Mount Vernon Harcourt, is a stratovolcano (1,570 m) making up part of the Hallett Peninsula, Victoria Land, Antarctica, extending into the Ross Sea about south of Mount Erebus, along with three overlapping shield volcanoes. It was discovered in January 1841 by Sir James Clark Ross and named by him for the Reverend William Vernon Harcourt, one of the founders of the British Association. Two dates have been obtained from the volcano's rock, roughly 5.5 and 6.6 million years in age. These samples are alkalic in composition. The volcano is known to be a"
"The Chilliwack Batholith is a large batholith that forms much of the North Cascades in southwestern British Columbia, Canada and the U.S. state of Washington. The geological structure is primarily named after the City of Chilliwack, where it is the most notable geological feature. The Chilliwack Batholith is part of the Pemberton Volcanic Belt and is the largest mass of exposed intrusive rock in the Cascade Volcanic Arc. The age of the Chilliwack batholith ranges from 26 to 29 million years old. In 2013, ""Maclean's"" reported that, with an average annual temperature of 10.5 °C, Chilliwack is the warmest city"
"from a high elevation plateau or basin accumulation zone to a lower valley ablation zone. Much larger icefalls may be found in the outlet glaciers of continental ice sheets. The icefall feeding the Lambert Glacier in Antarctica (photograph at left) is 7 kilometres (4.4 mi) wide and 14 kilometres (9 mi) long, even though the elevation difference is only 400 metres (1,300 ft), a little more than half that of the Roosevelt Glacier icefall. Icefalls are climbed because of their beauty and the challenge they pose. In some cases, an icefall may provide the only feasible or the easiest route"
"Brinicle A brinicle (brine icicle, also known as ice stalactite) is a downward growing hollow tube of ice enclosing a plume of descending brine that is formed beneath developing sea ice. As sea water freezes in the polar oceans, salt brine concentrates are expelled from the sea ice, creating a downward flow of dense, extremely cold and saline water with a lower freezing point than the surrounding water. When this plume comes into contact with the neighboring ocean water, its extremely cold temperature causes ice to instantly form around the flow. This creates a hollow stalactite or icicle, referred to"
"from less than 1 m to about 10 m at a maximum above the surrounding area. Large forms tend to be considerably less conical than small ones. In places, palsas combine to form complexes several hundred meters in extent. The permafrost core contains ice lenses no thicker than 2–3 cm, though locally lenses up to almost 40 cm thick have been described. Palsas form in groups or ""fields"" and the individual palsa can show its age difference from the others. Palsa surfaces are frequently traversed by open cracks, caused by doming (dilation cracking), frost cracking, or desiccation. The vegetation of"
"Langjökull Langjökull (Icelandic for ""long glacier"") is the second largest ice cap in Iceland (953 km), after Vatnajökull. It is situated in the west of the Icelandic interior or Highlands of Iceland and can be seen clearly from Haukadalur. The glacier is located at . Its volume is 195 km³ and the ice is up to thick. The highest point of the ice cap (at Baldjökull at the northern end of Langjökull) is about above sea level. In the past, the largest recorded surface area was in 1840. The glacier is roughly parallel to the direction of the country's active"
"Lyons Cone Lyons Cone () is a cone shaped peak north-northeast of the Matterhorn, rising to on the ridge separating the heads of Lacroix Glacier, Newall Glacier, and Suess Glacier in the Asgard Range, Victoria Land, Antarctica. It was named by the Advisory Committee on Antarctic Names after American geochemist William Berry Lyons, a veteran of expeditions to the Himalayas, Greenland, Iceland, and Antarctica, 1980–97, and chief scientist of the McMurdo Dry Valleys Long-Term Ecological Research field team, 1993–97. As a member of a University of New Hampshire field party, 1988–89, Lyons participated in glaciochemical investigations that collected two ice"
"Ice cap An ice cap is a mass of ice that covers less than 50,000 km of land area (usually covering a highland area). Larger ice masses covering more than 50,000 km are termed ice sheets. Ice caps are not constrained by topographical features (i.e., they will lie over the top of mountains). By contrast, ice masses of similar size that ""are"" constrained by topographical features are known as ice fields. The ""dome"" of an ice cap is usually centred on the highest point of a massif. Ice flows away from this high point (the ice divide) towards the ice"
"() is a mountain, high, standing 4 mi NW of Mount Lecointe. Discovered by the British Antarctic Expedition (1907–09) under Shackleton, and named for Prince Roland Bonaparte, President of the Société de Géographie of Paris from 1910-1924. Inaccessible Cliffs () is a line of steep cliffs, interrupted by several glaciers, which form the northern escarpment of the range. The escarpment borders the southern side of the Nimrod Glacier which is very heavily crevassed. Named by the northern party of the New Zealand Geological Survey Antarctic Expedition (NZGSAE) (1961–62) because of their general inaccessibility. Mount Lecointe () is a conspicuous mountain,"
"High Arctic Large Igneous Province The High Arctic Large Igneous Province (HALIP) is a Cretaceous large igneous province in the Arctic. The region is divided into several smaller magmatic provinces. Svalbard, Franz Josef Land, Sverdrup Basin, Amerasian Basin, and northern Greenland (Peary Land) are some of the larger divisions. Today, HALIP covers an area greater than , making it one of the largest and most intense magmatic complexes on the planet. However, eroded volcanic sediments in sedimentary strata in Svalbard and Franz Josef Land suggest that an extremely large portion of HALIP volcanics have already been eroded away. The HALIP"
"McDonald Heights The McDonald Heights () are broad, mainly snow-covered heights about long and rising over between Cape Burks and Morris Head on the coast of Marie Byrd Land, Antarctica. The heights are bounded southward by Hull Glacier, Kirkpatrick Glacier and Johnson Glacier. The feature was photographed from aircraft of the United States Antarctic Service, 1939–41, was observed and partially mapped from the during February 1962, and was mapped in detail by the United States Geological Survey in 1965. The heights were named by the Advisory Committee on Antarctic Names after Captain Edwin A. McDonald, U.S. Navy, Deputy Commander of"