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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 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 glacial period (alternatively glacial or glaciation) is an interval of time (thousands of years) within an ice age that is marked by colder temperatures and glacier advances. Interglacials, on the other hand, are periods of warmer climate between glacial periods. The Last Glacial Period ended about 15,000 years ago. The Holocene is the current interglacial. A time with no glaciers on Earth is considered a greenhouse climate state. Quaternary Period Within the Quaternary, which started about 2.6 million years before present, there have been a number of glacials and interglacials. At least eight glacial cycles have occurred in the last 740,000 years alone. Penultimate Glacial Period The Penultimate Glacial Period (PGP) is the glacial period that occurred before the Last Glacial Period. It began about 194,000 years ago and ended 135,000 years ago, with the beginning of the Eemian interglacial. Last Glacial Period The last glacial period was the most recent glacial period ... [...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 ...[...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 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 or mineral habit 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. Glacial Striations The surface of rocks can have an altered appearance as a result of the movement of ice. They can show a polished looking surface scarred with glacial striations. Often these striations carved into the bedrock extend for long distances. The scars are a result of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chatter Mark
A chatter mark is one or, more commonly, a series of wedge shaped 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 which 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 w ... References ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Permian
The Permian ( ) is a geologic period and stratigraphic system which spans 47 million years from the end of the Carboniferous Period million years ago (Mya), to the beginning of the Triassic Period 251.9 Mya. It is the last period of the Paleozoic Era; the following Triassic Period belongs to the Mesozoic Era. The concept of the Permian was introduced in 1841 by geologist Sir Roderick Murchison, who named it after the region of Perm in Russia. The Permian witnessed the diversification of the two groups of amniotes, the synapsids and the sauropsids ( reptiles). The world at the time was dominated by the supercontinent Pangaea, which had formed due to the collision of Euramerica and Gondwana during the Carboniferous. Pangaea was surrounded by the superocean Panthalassa. The Carboniferous rainforest collapse left behind vast regions of desert within the continental interior. Amniotes, which could better cope with these drier conditions, rose to dominance in place of their am ... [...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 un ... [...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 minerals (hydrous aluminium phyllosilicates, e.g. kaolin, Al2 Si2 O5( 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 ( laminae) less than one centimeter in thickness. This property is called '' 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 more narrow 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 into thin layers, often splintery and usually parallel to the otherwise indistinguishable beddin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Quartz
Quartz is a hard, crystalline mineral composed of silica (silicon dioxide). The atoms are linked in a continuous framework of SiO4 silicon-oxygen tetrahedra, with each oxygen being shared between two tetrahedra, giving an overall chemical formula of SiO2. 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 classified as gemstones. Since antiquity, varieties of quartz have been the most commonly used minerals in the making of jewelry and hardstone carvings, especially in Eurasia. Quartz is the mineral defining the val ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Canton Of Valais
Valais ( , , ; frp, Valês; german: Wallis ), more formally the Canton of Valais,; german: Kanton Wallis; in other official Swiss languages outside Valais: it, (Canton) Vallese ; rm, (Chantun) Vallais. is one of the 26 cantons forming the Swiss Confederation. It is composed of thirteen districts and its capital and largest city is Sion. The flag of the canton is made of thirteen stars representing the districts, on a white-red background. Valais is situated in the southwestern part of the country. It borders the cantons of Vaud and Bern to the north, the cantons of 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 Alpine cantons, along with Ticino and the Grisons, which encompass a vast diversity of ecosystems. 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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Grimentz
Grimentz is a village in the district of Sierre in the Swiss canton of Valais. An independent municipality before, it merged on 1 January 2009 with neighboring Ayer, Chandolin, Saint Jean, Saint-Luc and Vissoie to form the municipality of Anniviers.Amtliches Gemeindeverzeichnis der Schweiz published by the Swiss Federal Statistical Office accessed 19 July 2011 History Grimentz is first mentioned in 1052 as ''Grimiens''. The village was formerly known by its German name ''Grimensi'', however, that name is no longer used.Geography [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glacial Grooves
Glacial striations or striae are scratches or gouges cut into bedrock by glacial Abrasion (geology), 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 effe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Moiry Glacier
The Moiry Glacier (french: Glacier de Moiry) is a 5 km long glacier (2005) situated in the Pennine Alps in the canton of Valais in Switzerland. In 1973 it had an area of 5.75 km2. See also *List of glaciers in Switzerland *Swiss Alps The Alpine region of Switzerland, conventionally referred to as the Swiss Alps (german: Schweizer Alpen, french: Alpes suisses, it, Alpi svizzere, rm, Alps svizras), represents a major natural feature of the country and is, along with the Swiss ... External linksSwiss glacier monitoring network Glaciers of Valais Glaciers of the Alps {{valais-glacier-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
