|
Gelisol
Gelisols are an order in USDA soil taxonomy. They are soils of very cold climates which are defined as containing permafrost within of the soil surface. The word "Gelisol" comes from the Latin meaning "to freeze", a reference to the process of cryoturbation that occurs from the alternating thawing and freezing characteristic of Gelisols. In the World Reference Base for Soil Resources (WRB), most Gelisols belong to the Cryosols. In soil taxonomy, Gelisols key out before the Histosols. In the WRB, the Histosols key out before the Cryosols. Organic permafrost soils are therefore Gelisols (Histels) in the soil taxonomy and Histosols (Cryic Histosols) in the WRB. Structurally, Gelisols may have a B horizon and more commonly have an A horizon and/or O horizon resting on the permafrost. Because soil organic matter accumulates in the upper layer, most Gelisols are black or dark brown in soil color, followed by a shallow mineral layer. Despite the influence of glaciation in mo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
USDA Soil Taxonomy
USDA soil taxonomy (ST) developed by the United States Department of Agriculture and the National Cooperative Soil Survey provides an elaborate Soil classification, classification of soil types according to several parameters (most commonly their properties) and in several levels: ''Order'', ''Suborder'', ''Great Group'', ''Subgroup'', ''Family'', and ''Soil series, Series''. The classification was originally developed by Guy D. Smith, Guy Donald Smith, former director of the U.S. Department of Agriculture's soil survey investigations. Discussion A taxonomy is an arrangement in a systematic manner; the United States Department of Agriculture, USDA soil taxonomy has six levels of classification. They are, from most general to specific: order, suborder, great group, subgroup, family and series. Soil properties that can be measured quantitatively are used in this classification system – they include: depth, moisture, temperature, texture, structure, cation exchange capacity, base ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cryoturbation
In gelisols (permafrost soils), cryoturbation (frost churning) refers to the mixing of materials from various horizons of the soil down to the bedrock due to freezing and thawing. Cryoturbation occurs to varying degrees in most gelisols. The cause of cryoturbation lies in the way in which the repeated freezing of the soil during autumn causes the formation of ice wedges at the most easily erodible parts of the parent rock. If the parent rock is hard, this can cause quite deep erosion of the rock over many years. As this process continues, during the summer when an active layer forms in the soil this eroded material can easily move both from the soil surface downward and from the permafrost table upward. As this process occurs, the upper soil material gradually dries out (because the soil moisture moves from the warm surface layer to the colder layer at the top of the permafrost) so that it forms a granular structure with many very distinctive crystalline shapes (such as ice len ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Histosol
In both the World Reference Base for Soil Resources (WRB) and the USDA soil taxonomy, a Histosol is a soil consisting primarily of organic materials. They are defined as having or more of organic soil material starting within 40 cm from the soil surface. In Soil Taxonomy, Gelisols key out before Histosols, and in WRB, Histosols key out before Cryosols. Therefore, organic permafrost soils belong to the Histosols in WRB (Cryic Histosols) and to the Gelisols (Histels) in Soil Taxonomy. Organic soil material has an organic carbon content (by weight) of 12 percent or more (Soil Taxonomy) or 20 percent or more (WRB). These materials include Muck (soil), muck (sapric soil material), mucky peat (hemic soil material), or peat (fibric soil material). Many Histosols show aquic conditions or artificial drainage, some (Folists in Soil Taxonomy and Folic Histosols in WRB) developed under terrestrial conditions. Organic material and therefore Histosols have very low bulk density. Many are ac ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Siberia
Siberia ( ; , ) is an extensive geographical region comprising all of North Asia, from the Ural Mountains in the west to the Pacific Ocean in the east. It has formed a part of the sovereign territory of Russia and its predecessor states since the lengthy conquest of Siberia, which began with the fall of the Khanate of Sibir in 1582 and concluded with the annexation of Chukotka in 1778. Siberia is vast and sparsely populated, covering an area of over , but home to roughly a quarter of Russia's population. Novosibirsk, Krasnoyarsk, and Omsk are the largest cities in the area. Because Siberia is a geographic and historic concept and not a political entity, there is no single precise definition of its territorial borders. Traditionally, Siberia spans the entire expanse of land from the Ural Mountains to the Pacific Ocean, with the Ural River usually forming the southernmost portion of its western boundary, and includes most of the drainage basin of the Arctic Ocean. I ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Greenland
Greenland is an autonomous territory in the Danish Realm, Kingdom of Denmark. It is by far the largest geographically of three constituent parts of the kingdom; the other two are metropolitan Denmark and the Faroe Islands. Citizens of Greenland are full Danish nationality law, citizens of Denmark and European Union citizenship, of the European Union. Greenland is one of the Special territories of members of the European Economic Area#Overseas countries and territories, Overseas Countries and Territories of the European Union and is part of the Council of Europe. It is the List of islands by area, world's largest island, and lies between the Arctic Ocean, Arctic and Atlantic oceans, east of the Arctic Archipelago, Canadian Arctic Archipelago. It is the location of the northernmost point of land in the world; Kaffeklubben Island off the northern coast is the world's Northernmost point of land, northernmost undisputed point of land—Cape Morris Jesup on the mainland was thought to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Scandinavia
Scandinavia is a subregion#Europe, subregion of northern Europe, with strong historical, cultural, and linguistic ties between its constituent peoples. ''Scandinavia'' most commonly refers to Denmark, Norway, and Sweden. It can sometimes also refer to the Scandinavian Peninsula (which excludes Denmark but includes a part of northern Finland). In English usage, Scandinavia is sometimes used as a synonym for Nordic countries. Iceland and the Faroe Islands are sometimes included in Scandinavia for their Ethnolinguistics, ethnolinguistic relations with Sweden, Norway and Denmark. While Finland differs from other Nordic countries in this respect, some authors call it Scandinavian due to its economic and cultural similarities. The geography of the region is varied, from the Norwegian fjords in the west and Scandinavian mountains covering parts of Norway and Sweden, to the low and flat areas of Denmark in the south, as well as archipelagos and lakes in the east. Most of the population ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tibet
Tibet (; ''Böd''; ), or Greater Tibet, is a region in the western part of East Asia, covering much of the Tibetan Plateau and spanning about . It is the homeland of the Tibetan people. Also resident on the plateau are other ethnic groups such as Mongols, Monpa people, Monpa, Tamang people, Tamang, Qiang people, Qiang, Sherpa people, Sherpa, Lhoba people, Lhoba, and since the 20th century Han Chinese and Hui people, Hui. Tibet is the highest region on Earth, with an average elevation of . Located in the Himalayas, the highest elevation in Tibet is Mount Everest, Earth's highest mountain, rising above sea level. The Tibetan Empire emerged in the 7th century. At its height in the 9th century, the Tibetan Empire extended far beyond the Tibetan Plateau, from the Tarim Basin and Pamirs in the west, to Yunnan and Bengal in the southeast. It then divided into a variety of territories. The bulk of western and central Tibet (Ü-Tsang) was often at least nominally unified under a ser ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Argentina
Argentina, officially the Argentine Republic, is a country in the southern half of South America. It covers an area of , making it the List of South American countries by area, second-largest country in South America after Brazil, the fourth-largest country in the Americas, and the List of countries and dependencies by area, eighth-largest country in the world. Argentina shares the bulk of the Southern Cone with Chile to the west, and is also bordered by Bolivia and Paraguay to the north, Brazil to the northeast, Uruguay and the South Atlantic Ocean to the east, and the Drake Passage to the south. Argentina is a Federation, federal state subdivided into twenty-three Provinces of Argentina, provinces, and one autonomous city, which is the federal capital and List of cities in Argentina by population, largest city of the nation, Buenos Aires. The provinces and the capital have their own constitutions, but exist under a Federalism, federal system. Argentina claims sovereignty ov ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bolivia
Bolivia, officially the Plurinational State of Bolivia, is a landlocked country located in central South America. The country features diverse geography, including vast Amazonian plains, tropical lowlands, mountains, the Gran Chaco Province, warm valleys, high-altitude Andean plateaus, and snow-capped peaks, encompassing a wide range of climates and biomes across its regions and cities. It includes part of the Pantanal, the largest tropical wetland in the world, along its eastern border. It is bordered by Brazil to the Bolivia-Brazil border, north and east, Paraguay to the southeast, Argentina to the Argentina-Bolivia border, south, Chile to the Bolivia–Chile border, southwest, and Peru to the west. The seat of government is La Paz, which contains the executive, legislative, and electoral branches of government, while the constitutional capital is Sucre, the seat of the judiciary. The largest city and principal industrial center is Santa Cruz de la Sierra, located on the Geog ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chile
Chile, officially the Republic of Chile, is a country in western South America. It is the southernmost country in the world and the closest to Antarctica, stretching along a narrow strip of land between the Andes, Andes Mountains and the Pacific Ocean. Chile had a population of 17.5 million as of the latest census in 2017 and has a territorial area of , sharing borders with Peru to the north, Bolivia to the northeast, Argentina to the east, and the Drake Passage to the south. The country also controls several Pacific islands, including Juan Fernández Islands, Juan Fernández, Isla Salas y Gómez, Desventuradas Islands, Desventuradas, and Easter Island, and claims about of Antarctica as the Chilean Antarctic Territory. The capital and largest city of Chile is Santiago, and the national language is Spanish language, Spanish. Conquest of Chile, Spain conquered and colonized the region in the mid-16th century, replacing Incas in Central Chile, Inca rule; however, they Arauco War ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Andes
The Andes ( ), Andes Mountains or Andean Mountain Range (; ) are the List of longest mountain chains on Earth, longest continental mountain range in the world, forming a continuous highland along the western edge of South America. The range is long and wide (widest between 18th parallel south, 18°S and 20th parallel south, 20°S latitude) and has an average height of about . The Andes extend from south to north through seven South American countries: Argentina, Chile, Bolivia, Peru, Ecuador, Colombia, and Venezuela. Along their length, the Andes are split into several ranges, separated by intermediate depression (geology), depressions. The Andes are the location of several high plateaus—some of which host major cities such as Quito, Bogotá, Cali, Arequipa, Medellín, Bucaramanga, Sucre, Mérida, Mérida, Mérida, El Alto, and La Paz. The Altiplano, Altiplano Plateau is the world's second highest after the Tibetan Plateau. These ranges are in turn grouped into three majo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Canada
Canada is a country in North America. Its Provinces and territories of Canada, ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, making it the world's List of countries and dependencies by area, second-largest country by total area, with the List of countries by length of coastline, world's longest coastline. Its Canada–United States border, border with the United States is the world's longest international land border. The country is characterized by a wide range of both Temperature in Canada, meteorologic and Geography of Canada, geological regions. With Population of Canada, a population of over 41million people, it has widely varying population densities, with the majority residing in List of the largest population centres in Canada, urban areas and large areas of the country being sparsely populated. Canada's capital is Ottawa and List of census metropolitan areas and agglomerations in Canada, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
