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Glacial Striations
Glacial striations or striae are scratches or gouges cut into bedrock by glacial abrasion. These scratches and gouges were first recognized as the result of a moving glacier in the late 18th century when Swiss alpinists first associated them with moving glaciers. They also noted that if they were visible today that the glaciers must also be receding. Glacial striations are usually multiple, straight, and parallel, representing the movement of the glacier using rock fragments and sand grains, embedded in the base of the glacier, as cutting tools. Large amounts of coarse gravel and boulders carried along underneath the glacier provide the abrasive power to cut trough-like ''glacial grooves''. Finer sediments also in the base of the moving glacier further scour and polish the bedrock surface, forming a ''glacial pavement''. Ice itself is not a hard enough material to change the shape of rock but because the ice has rock embedded in the basal surface it can effectively abrade the b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glacial Striation 21149
A glacier (; or ) is a persistent body of dense ice, a form of rock, that is constantly moving downhill under its own weight. A glacier forms where the accumulation of snow exceeds its ablation over many years, often centuries. It acquires distinguishing features, such as crevasses and seracs, as it slowly flows and deforms under stresses induced by its weight. As it moves, it abrades rock and debris from its substrate to create landforms such as cirques, moraines, or fjords. Although a glacier may flow into a body of water, it forms only on land“Glacier, N., Pronunciation.” Oxford English Dictionary, Oxford UP, June 2024, https://doi.org/10.1093/OED/7553486115. Accessed 25 Jan. 2025. and is distinct from the much thinner sea ice and lake ice that form on the surface of bodies of water. On Earth, 99% of glacial ice is contained within vast ice sheets (also known as "continental glaciers") in the polar regions, but glaciers may be found in mountain ranges on every continen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Canton Of Valais
Valais ( , ; ), more formally, the Canton of Valais or Wallis, is one of the cantons of Switzerland, 26 cantons forming the Switzerland, Swiss Confederation. It is composed of thirteen districts and its capital and largest city is Sion, Switzerland, Sion. Valais is situated in the southwestern part of the country. It borders the cantons of Canton of Vaud, Vaud and Canton of Bern, Bern to the north, the cantons of Canton of Uri, Uri and Ticino to the east, as well as Italy to the south and France to the west. It is one of the three large southern Alps, Alpine cantons, along with Ticino and Grisons. It is a bilingual canton, French and German being its two official languages. Traditionally, the canton is divided into Lower, Central, and Upper Valais, the latter region constituting the German-speaking minority. Valais is essentially coextensive with the valley of the Rhône from its headwaters to Lake Geneva, separating the Pennine Alps from the Bernese Alps, the two largest mount ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Striation (geology)
In geology, a striation is a groove, created by a geological process, on the surface of a rock or a mineral. In structural geology, striations are linear furrows, or linear marks, generated from Fault (geology), fault movement. The striation's direction reveals the movement direction in the fault plane. Similar striations, called glacial striations, can occur in areas subjected to glaciation. Striations can also be caused by underwater landslides. Striations can also be a growth pattern that looks like a set of hairline grooves, seen on crystal faces of certain minerals. Examples of minerals that can show growth striations include pyrite, feldspar, quartz, tourmaline, chalcocite and sphalerite. See also *Slickenside Bibliography External links Structural geology Mineralogy Glacial erosion landforms {{struct-geology-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chatter Mark
In glacial geology, a chatter mark is a wedge-shaped mark (usually of a series of such marks) left by chipping of a bedrock surface by rock fragments carried in the base of a glacier ( glacial plucking). Marks tend to be crescent-shaped and oriented at right angles to the direction of ice movement.Marshak, Stephen, 2009, Essentials of Geology, W. W. Norton & Company, 3rd ed. There are three different types of chatter marks. The crescentic gouge is an upstream concave that is made by the removal of a piece of rock. The crescentic fracture is a downstream concave that is also made by the removal of rock. The lunate fracture is also a downstream concave made without the removal of rock. See also * Glacial polish *Glacial striation Glacial striations or striae are scratches or gouges cut into bedrock by glacial abrasion. These scratches and gouges were first recognized as the result of a moving glacier in the late 18th century when Swiss alpinists first associated them ... ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sault Plat River
The Sault Plat River () flows north/south on the north shore of the Gulf of St. Lawrence, in Sept-Rivières Regional County Municipality, Sept-Rivières and Minganie Regional County Municipality, Minganie RCM, in Côte-Nord region, Quebec, Canada. Part of the river is located in the municipality of Rivière-au-Tonnerre, Quebec, Rivière-au-Tonnerre, and is visible from Quebec Route 138#The Whale Route, The Whale Route (138). Toponymy The toponym "Rivière du Sault Plat" was made official on December 5, 1968 in the place name bank of the Commission de toponymie du Québec. The name first appeared officially on a map in 1969 in the ''Répertoire géographique du Québec''. The river was not named on 1913 & 1927 maps by Gustave Rinfret or Edgar Rochette (1890-1953). Geology and geomorphology Considered a geological heritage, the furrows of Erosion, glacial erosion in the rock where the Plat de Sault River flows make it of exceptional geological interest. The site offers remarkable ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Canadian Shield
The Canadian Shield ( ), also called the Laurentian Shield or the Laurentian Plateau, is a geologic shield, a large area of exposed Precambrian igneous and high-grade metamorphic rocks. It forms the North American Craton (or Laurentia), the ancient geologic core of the North American continent. Glaciation has left the area with only a thin layer of soil, through which exposures of igneous bedrock resulting from its long volcanic history are frequently visible. As a deep, common, joined bedrock region in eastern and central Canada, the shield stretches north from the Great Lakes to the Arctic Ocean, covering over half of Canada and most of Greenland; it also extends south into the northern reaches of the continental United States. Geographical extent The Canadian Shield is a physiographic division comprising four smaller physiographic provinces: the Laurentian Upland, Kazan Region, Davis and James. The shield extends into the United States as the Adirondack Mountains ( ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Inman Valley, South Australia
Inman Valley is a locality in the Australian state of South Australia located on the Fleurieu Peninsula about south of the state capital of Adelaide. The valley is about in area. At the 2016 census, Inman Valley had a population of 343. Origin of the name Inman Valley, and Inman River, was named through association with Inspector Henry Inman, founder and first commander of the South Australia Police, who pursued two allegedly escaped convicts there in August 1838. No Indigenous name is recorded for the valley itself, but two names are recorded for the river: Moo-oola and Moogoora. The mouth was called Mugurank, meaning 'place of hammerstones'. History The first recorded Europeans to sight the valley were likely the party that accompanied explorer Collet Barker (but not Barker himself) in 1831. In its pristine state the valley abounded in kangaroos, which were hunted for food by early sealers and whalers at Encounter Bay. Inman Valley was surveyed in late 1839 by a party u ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Shale
Shale is a fine-grained, clastic sedimentary rock formed from mud that is a mix of flakes of Clay mineral, clay minerals (hydrous aluminium phyllosilicates, e.g., Kaolinite, kaolin, aluminium, Al2Silicon, Si2Oxygen, O5(hydroxide, OH)4) and tiny fragments (silt-sized particles) of other minerals, especially quartz and calcite.Blatt, Harvey and Robert J. Tracy (1996) ''Petrology: Igneous, Sedimentary and Metamorphic'', 2nd ed., Freeman, pp. 281–292 Shale is characterized by its tendency to split into thin layers (Lamination (geology), laminae) less than one centimeter in thickness. This property is called ''Fissility (geology), fissility''. Shale is the most common sedimentary rock. The term ''shale'' is sometimes applied more broadly, as essentially a synonym for mudrock, rather than in the narrower sense of clay-rich fissile mudrock. Texture Shale typically exhibits varying degrees of fissility. Because of the parallel orientation of clay mineral flakes in shale, it breaks in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Quartz
Quartz is a hard, crystalline mineral composed of silica (silicon dioxide). The Atom, atoms are linked in a continuous framework of SiO4 silicon–oxygen Tetrahedral molecular geometry, tetrahedra, with each oxygen being shared between two tetrahedra, giving an overall chemical formula of Silicon dioxide, SiO2. Quartz is, therefore, classified structurally as a Silicate mineral#Tectosilicates, framework silicate mineral and compositionally as an oxide mineral. Quartz is the second most abundant mineral in Earth's continental crust, behind feldspar. Quartz exists in two forms, the normal α-quartz and the high-temperature β-quartz, both of which are chiral. The transformation from α-quartz to β-quartz takes place abruptly at . Since the transformation is accompanied by a significant change in volume, it can easily induce microfracturing of ceramics or rocks passing through this temperature threshold. There are many different varieties of quartz, several of which are classifi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anniviers
Anniviers is a municipality in the district of Sierre in the canton of Valais in Switzerland. It was formed through the merger of six municipalities in Val d'Anniviers: Ayer, Chandolin, Grimentz, Saint-Jean, Saint-Luc and Vissoie. The merger became effective 1 January 2009,Amtliches Gemeindeverzeichnis der Schweiz published by the Swiss Federal Statistical Office accessed 19 July 2011 creating the third largest municipality of Switzerland by area. History Human settlement dates from the and |
Glacial Grooves
Glacial striations or striae are scratches or gouges cut into bedrock by glacial abrasion. These scratches and gouges were first recognized as the result of a moving glacier in the late 18th century when Swiss alpinists first associated them with moving glaciers. They also noted that if they were visible today that the glaciers must also be receding. Glacial striations are usually multiple, straight, and parallel, representing the movement of the glacier using rock fragments and sand grains, embedded in the base of the glacier, as cutting tools. Large amounts of coarse gravel and boulders carried along underneath the glacier provide the abrasive power to cut trough-like ''glacial grooves''. Finer sediments also in the base of the moving glacier further scour and polish the bedrock surface, forming a ''glacial pavement''. Ice itself is not a hard enough material to change the shape of rock but because the ice has rock embedded in the basal surface it can effectively abrade the b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
