|
Glaciers
A glacier (; ) is a persistent body of dense ice that is constantly moving 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 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 continent other than the Australian mainland, including Oceania's high-latitude oceanic island countries such as New Zealand. Between latitudes 35°N and 35°S, glaciers occur onl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Himalayas
The Himalayas, or Himalaya (; ; ), is a mountain range in Asia, separating the plains of the Indian subcontinent from the Tibetan Plateau. The range has some of the planet's highest peaks, including the very highest, Mount Everest. Over 100 peaks exceeding in elevation lie in the Himalayas. By contrast, the highest peak outside Asia (Aconcagua, in the Andes) is tall. The Himalayas abut or cross five countries: Bhutan, India, Nepal, China, and Pakistan. The sovereignty of the range in the Kashmir region is disputed among India, Pakistan, and China. The Himalayan range is bordered on the northwest by the Karakoram and Hindu Kush ranges, on the north by the Tibetan Plateau, and on the south by the Indo-Gangetic Plain. Some of the world's major rivers, the Indus, the Ganges, and the Tsangpo– Brahmaputra, rise in the vicinity of the Himalayas, and their combined drainage basin is home to some 600 million people; 53 million people live in the Himalayas. The Himalayas ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
New Guinea
New Guinea (; Hiri Motu: ''Niu Gini''; id, Papua, or , historically ) is the world's second-largest island with an area of . Located in Oceania in the southwestern Pacific Ocean, the island is separated from Australia by the wide Torres Strait, though both landmasses lie on the same continental shelf. Numerous smaller islands are located to the west and east. The eastern half of the island is the major land mass of the independent state of Papua New Guinea. The western half, known as Western New Guinea, forms a part of Indonesia and is organized as the provinces of Papua, Central Papua, Highland Papua, South Papua, Southwest Papua, and West Papua. The largest cities on the island are Jayapura (capital of Papua, Indonesia) and Port Moresby (capital of Papua New Guinea). Names The island has been known by various names: The name ''Papua'' was used to refer to parts of the island before contact with the West. Its etymology is unclear; one theory states that ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Crevasse
A crevasse is a deep crack, that forms in a glacier or ice sheet that can be a few inches across to over 40 feet. Crevasses form as a result of the movement and resulting stress associated with the shear stress generated when two semi-rigid pieces above a plastic substrate have different rates of movement. The resulting intensity of the shear stress causes a breakage along the faces. Description Crevasses often have vertical or near-vertical walls, which can then melt and create seracs, arches, and other ice formations. These walls sometimes expose layers that represent the glacier's stratigraphy. Crevasse size often depends upon the amount of liquid water present in the glacier. A crevasse may be as deep as 45 metres and as wide as 20 metres. by [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ice Sheet
In glaciology, an ice sheet, also known as a continental glacier, is a mass of glacial ice that covers surrounding terrain and is greater than . The only current ice sheets are in Antarctica and Greenland; during the Last Glacial Period at Last Glacial Maximum, the Laurentide Ice Sheet covered much of North America, the Weichselian ice sheet covered Northern Europe and the Patagonian Ice Sheet covered southern South America. Ice sheets are bigger than ice shelves or alpine glaciers. Masses of ice covering less than 50,000 km2 are termed an ice cap. An ice cap will typically feed a series of glaciers around its periphery. Although the surface is cold, the base of an ice sheet is generally warmer due to geothermal heat. In places, melting occurs and the melt-water lubricates the ice sheet so that it flows more rapidly. This process produces fast-flowing channels in the ice sheet — these are ice streams. The present-day polar ice sheets are relatively young in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Moraine
A moraine is any accumulation of unconsolidated debris ( regolith and rock), sometimes referred to as glacial till, that occurs in both currently and formerly glaciated regions, and that has been previously carried along by a glacier or ice sheet. It may consist of partly rounded particles ranging in size from boulders (in which case it is often referred to as boulder clay) down to gravel and sand, in a groundmass of finely-divided clayey material sometimes called glacial flour. Lateral moraines are those formed at the side of the ice flow, and terminal moraines were formed at the foot, marking the maximum advance of the glacier. Other types of moraine include ground moraines ( till-covered areas forming sheets on flat or irregular topography) and medial moraines (moraines formed where two glaciers meet). Etymology The word ''moraine'' is borrowed from French , which in turn is derived from the Savoyard Italian ("mound of earth"). ''Morena'' in this case was derived from Pr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Zard-Kuh
Zard-Kuh (meaning "Yellow Mountain", also spelled Zardkuh, Zarduh Kuh or Zard Kuh-e Bakhtiari; Persian: زردکوه بختیاری) is a sub-range in the central Zagros Range, Iran. With an elevation of 4221 metres, the Zard-Kuh is located in the Zagros Mountains in the Chaharmahal and Bakhtiari Province of Iran. The Karun and also Zayanderud rivers start in the Zagros mountains near the Zard-Kuh. There are small glaciers on the mountain owing to the relatively high precipitation, which are the only glaciers in the subtropics outside the Himalayas, Andes and Trans-Mexican Volcanic Belt. Geologically, the Zard-Kuh is situated in the Sanandaj- Sirjan geologic and structural zone of Iran and is mainly made of Cretaceous limestone.Geological Map of Iran, National Geoscience Database of Iran, www.ngdir.ir The famous early documentary ''Grass'' captures on film the Bakhtiari tribe's crossing of Zard-Kuh barefoot in the snow with 50,000 people and 125,000 animals. See also * ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Antarctica
Antarctica () is Earth's southernmost and least-populated continent. Situated almost entirely south of the Antarctic Circle and surrounded by the Southern Ocean, it contains the geographic South Pole. Antarctica is the fifth-largest continent, being about 40% larger than Europe, and has an area of . Most of Antarctica is covered by the Antarctic ice sheet, with an average thickness of . Antarctica is, on average, the coldest, driest, and windiest of the continents, and it has the highest average elevation. It is mainly a polar desert, with annual precipitation of over along the coast and far less inland. About 70% of the world's freshwater reserves are frozen in Antarctica, which, if melted, would raise global sea levels by almost . Antarctica holds the record for the lowest measured temperature on Earth, . The coastal regions can reach temperatures over in summer. Native species of animals include mites, nematodes, penguins, seals and tardigrades. Where ve ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Serac
A serac (from Swiss French ''sérac'') is a block or column of glacial ice, often formed by intersecting crevasses on a glacier. Commonly house-sized or larger, they are dangerous to mountaineers, since they may topple with little warning. Even when stabilized by persistent cold weather, they can be an impediment to glacier travel. Seracs are found within an icefall, often in large numbers, or on ice faces on the lower edge of a hanging glacier. Notable examples of the overhanging glacier edge type are well-known obstacles on some of the world's highest mountains, including K2 at " The Bottleneck" and Kanchenjunga on the border of India and Nepal. Significant seracs in the Alps are found on the northeast face of Piz Roseg, the north face of the Dent d'Hérens, and the north face of Lyskamm. Incidents * On a 1969–1970 Japanese expedition to Mount Everest, Kyak Tsering was killed by a falling serac. * In 1990, an earthquake caused a block of serac to fall off Lenin Peak, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cirque
A (; from the Latin word ') is an amphitheatre-like valley formed by glacial erosion. Alternative names for this landform are corrie (from Scottish Gaelic , meaning a pot or cauldron) and (; ). A cirque may also be a similarly shaped landform arising from fluvial erosion. The concave shape of a glacial cirque is open on the downhill side, while the cupped section is generally steep. Cliff-like slopes, down which ice and glaciated debris combine and converge, form the three or more higher sides. The floor of the cirque ends up bowl-shaped, as it is the complex convergence zone of combining ice flows from multiple directions and their accompanying rock burdens. Hence, it experiences somewhat greater erosion forces and is most often overdeepened below the level of the cirque's low-side outlet (stage) and its down-slope (backstage) valley. If the cirque is subject to seasonal melting, the floor of the cirque most often forms a tarn (small lake) behind a dam, which marks the d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ablation
Ablation ( la, ablatio – removal) is removal or destruction of something from an object by vaporization, chipping, erosive processes or by other means. Examples of ablative materials are described below, and include spacecraft material for ascent and atmospheric reentry, ice and snow in glaciology, biological tissues in medicine and passive fire protection materials. Artificial intelligence In artificial intelligence (AI), especially machine learning, ablation is the removal of a component of an AI system. The term is by analogy with biology: removal of components of an organism. Biology Biological ablation is the removal of a biological structure or functionality. Genetic ablation is another term for gene silencing, in which gene expression is abolished through the alteration or deletion of genetic sequence information. In cell ablation, individual cells in a population or culture are destroyed or removed. Both can be used as experimental tools, as in loss-of-functi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Water Resources
Water resources are natural resources of water that are potentially useful for humans, for example as a source of drinking water supply or irrigation water. 97% of the water on the Earth is salt water and only three percent is fresh water; slightly over two thirds of this is frozen in glaciers and polar ice caps. The remaining unfrozen freshwater is found mainly as groundwater, with only a small fraction present above ground or in the air. Natural sources of fresh water include surface water, under river flow, groundwater and frozen water. Artificial sources of fresh water can include treated wastewater ( wastewater reuse) and desalinated seawater. Human uses of water resources include agricultural, industrial, household, recreational and environmental activities. Water resources are under threat from water scarcity, water pollution, water conflict and climate change. Fresh water is a renewable resource, yet the world's supply of groundwater is steadily decreasing, with dep ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Meltwater
Meltwater is water released by the melting of snow or ice, including glacial ice, tabular icebergs and ice shelves over oceans. Meltwater is often found in the ablation zone of glaciers, where the rate of snow cover is reducing. Meltwater can be produced during volcanic eruptions, in a similar way in which the more dangerous lahars form. When meltwater pools on the surface rather than flowing, it forms melt ponds. As the weather gets colder meltwater will often re-freeze. Meltwater can collect or melt under the ice's surface. These pools of water, known as subglacial lakes can form due to geothermal heat and friction. Water source Meltwater provides drinking water for a large proportion of the world's population, as well as providing water for irrigation and hydroelectric plants. This meltwater can originate from seasonal snowfall, or from the melting of more permanent glaciers. Climate change threatens the precipitation of snow and the shrinking volume of glaciers. So ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
.JPG "Click for more on -> Moraine")
