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Mass Wasting
Mass wasting, also known as mass movement, is a general term for the movement of rock or soil down slopes under the force of gravity. It differs from other processes of erosion in that the debris transported by mass wasting is not entrained in a moving medium, such as water, wind, or ice. Types of mass wasting include creep, solifluction, rockfalls, debris flows, and landslides, each with its own characteristic features, and taking place over timescales from seconds to hundreds of years. Mass wasting occurs on both terrestrial and submarine slopes, and has been observed on Earth, Mars, Venus, Jupiter's moons Io, and on many other bodies in the Solar System. Subsidence is sometimes regarded as a form of mass wasting. A distinction is then made between mass wasting by subsidence, which involves little horizontal movement, and mass wasting by slope movement. Rapid mass wasting events, such as landslides, can be deadly and destructive. More gradual mass wasting, such as soil ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Solar System
The Solar System Capitalization of the name varies. The International Astronomical Union, the authoritative body regarding astronomical nomenclature, specifies capitalizing the names of all individual astronomical objects but uses mixed "Solar System" and "solar system" structures in theinaming guidelines document. The name is commonly rendered in lower case ('solar system'), as, for example, in the ''Oxford English Dictionary'' an''Merriam-Webster's 11th Collegiate Dictionary''. is the gravitationally bound system of the Sun and the objects that orbit it. It formed 4.6 billion years ago from the gravitational collapse of a giant interstellar molecular cloud. The vast majority (99.86%) of the system's mass is in the Sun, with most of the remaining mass contained in the planet Jupiter. The four inner system planets— Mercury, Venus, Earth and Mars—are terrestrial planets, being composed primarily of rock and metal. The four giant planets of the outer system are ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thistle 2010 From US6 Rest Area
Thistle is the common name of a group of flowering plants characterised by leaves with sharp prickles on the margins, mostly in the family Asteraceae. Prickles can also occur all over the planton the stem and on the flat parts of the leaves. These prickles are an adaptation that protects the plant from being eaten by herbivores. Typically, an involucre with a clasping shape similar to a cup or urn subtends each of a thistle's flower heads. The comparative amount of spininess varies dramatically by species. For example, ''Cirsium heterophyllum'' has minimal spininess while '' Cirsium spinosissimum'' is the opposite. Typically, species adapted to dry environments have greater spininess. The term thistle is sometimes taken to mean precisely those plants in the tribe Cardueae (synonym: Cynareae), especially the genera ''Carduus'', ''Cirsium'', and '' Onopordum''. However, plants outside this tribe are sometimes called thistles. Biennial thistles are particularly noteworthy for ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stone Rivers
A stone run (called also ''stone river'', ''stone stream'' or ''stone sea''Vitosha Nature Park: Basic Information. Landscape. Vitosha Nature Park website.) is a rock landform resulting from the of particular rock varieties caused by freezing-thawing cycles in periglacial conditions during the last Ice Age. The actual formation of stone runs involved five processes: , < ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Weathering
Weathering is the deterioration of rocks, soils and minerals as well as wood and artificial materials through contact with water, atmospheric gases, and biological organisms. Weathering occurs ''in situ'' (on site, with little or no movement), and so is distinct from erosion, which involves the transport of rocks and minerals by agents such as water, ice, snow, wind, waves and gravity. Weathering processes are divided into ''physical'' and ''chemical weathering''. Physical weathering involves the breakdown of rocks and soils through the mechanical effects of heat, water, ice, or other agents. Chemical weathering involves the chemical reaction of water, atmospheric gases, and biologically produced chemicals with rocks and soils. Water is the principal agent behind both physical and chemical weathering, though atmospheric oxygen and carbon dioxide and the activities of biological organisms are also important. Chemical weathering by biological action is also known as biologic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Permafrost
Permafrost is ground that continuously remains below 0 °C (32 °F) for two or more years, located on land or under the ocean. Most common in the Northern Hemisphere, around 15% of the Northern Hemisphere or 11% of the global surface is underlain by permafrost, with the total area of around 18 million km2. This includes substantial areas of Alaska, Greenland, Canada and Siberia. It can also be located on mountaintops in the Southern Hemisphere and beneath ice-free areas in the Antarctic. Permafrost does not have to be the first layer that is on the ground. It can be from an inch to several miles deep under the Earth's surface. It frequently occurs in ground ice, but it can also be present in non-porous bedrock. Permafrost is formed from ice holding various types of soil, sand, and rock in combination. Permafrost contains large amounts of biomass and decomposed biomass that has been stored as methane and carbon dioxide, making tundra soil a carbon sink. As global wa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sloughing (soil)
Soil sloughing is soil falling off banks and slopes due to a loss in cohesion. Soil sloughs off for the same reasons as landslides in general, with very wet soil being among the leading factors. Sloughing is a relatively shallow phenomenon involving the uppermost layers of the soil. Bare soils are more likely to slough than soils with plant cover in part because the roots help hold the surface against gravity. Unabated soil sloughing can end in massive bank or slope failure. Impact on soil quality According to the Mohr-Coulomb equation, the cohesion of a soil is defined as the shear strength at zero normal pressure on the surface of failure. The shear force is a function of cohesion, normal stress on rupture surface, and angle of internal friction. Shear force is significantly impacted by drainage conditions. Increasing water content would lead to a weaker shear strength, which in turn decreases the cohesion. Moreover, when the soil water content passes a threshold value, the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Terracette
A terracette is a landform consisting of a hillside ridge arranged as part of sub-parallel "step-like sequences" of such ridges. Terracette occur on step hillsides and are regularly spaced. Various causes have been suggested to explain their origin including: animal trampling, vegetation and regolith behaviour, soil creep and solifluction including gelifluction. One explanation holds that terracettes are formed when saturated soil particles expand, then contract as they dry, causing them to move slowly downhill. An example of this is the manger near the Uffington White Horse. It may also be described as a small, irregular step-like formation on steep hillslopes, especially on those used for pasture which are formed by soil creep or erosion of surface soils exacerbated by the trampling of livestock such as sheep or cattle. Synonyms are: catstep cattle terracing, sheep or cattle track. Early investigators such as C. Darwin (1904) believed that animals grazing the hillsides caused ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Grand Mesa Creep
Grand may refer to: People with the name * Grand (surname) * Grand L. Bush (born 1955), American actor * Grand Mixer DXT, American turntablist * Grand Puba (born 1966), American rapper Places * Grand, Oklahoma * Grand, Vosges, village and commune in France with Gallo-Roman amphitheatre * Grand Concourse (other), several places * Grand County (other), several places * Grand Geyser, Upper Geyser Basin of Yellowstone * Grand Rounds National Scenic Byway, a parkway system in Minneapolis, Minnesota, United States * Le Grand, California, census-designated place * Grand Staircase, a place in the US. Arts, entertainment, and media * ''Grand'' (Erin McKeown album), 2003 * ''Grand'' (Matt and Kim album), 2009 * ''Grand'' (magazine), a lifestyle magazine related to related to grandparents * ''Grand'' (TV series), American sitcom, 1990 * Grand piano, musical instrument * Grand Production, Serbian record label company * The Grand Tour, a new British automobile show ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stream
A stream is a continuous body of surface water flowing within the bed and banks of a channel. Depending on its location or certain characteristics, a stream may be referred to by a variety of local or regional names. Long large streams are usually called rivers, while smaller, less voluminous and more intermittent streams are known as streamlets, brooks or creeks. The flow of a stream is controlled by three inputs – surface runoff (from precipitation or meltwater), daylighted subterranean water, and surfaced groundwater ( spring water). The surface and subterranean water are highly variable between periods of rainfall. Groundwater, on the other hand, has a relatively constant input and is controlled more by long-term patterns of precipitation. The stream encompasses surface, subsurface and groundwater fluxes that respond to geological, geomorphological, hydrological and biotic controls. Streams are important as conduits in the water cycle, instruments in groundw ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mudflow
A mudflow or mud flow is a form of mass wasting involving fast-moving flow of debris that has become liquified by the addition of water. Such flows can move at speeds ranging from 3 meters/minute to 5 meters/second. Mudflows contain a significant proportion of clay, which makes them more fluid than debris flows, allowing them to travel farther and across lower slope angles. Both types of flow are generally mixtures of particles with a wide range of sizes, which typically become sorted by size upon deposition. Mudflows are often called mudslides, a term applied indiscriminately by the mass media to a variety of mass wasting events. Mudflows often start as slides, becoming flows as water is entrained along the flow path; such events are often called flow slides. Other types of mudflows include lahars (involving fine-grained pyroclastic deposits on the flanks of volcanoes) and jökulhlaups (outbursts from under glaciers or icecaps). A statutory definition of "flood-related muds ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Afforestation
Afforestation is the establishment of a forest or stand of trees ( forestation) in an area where there was no previous tree cover. Many government and non-governmental organizations directly engage in afforestation programs to create forests and increase carbon capture. Afforestation is an increasingly sought-after method to fight climate concerns, as it is known to increase the soil quality and organic carbon levels into the soil, avoiding desertification. Afforestation is mainly done for conservational and commercial purposes. # The rate of net forest loss decreased substantially over the period 1990–2020 due to a reduction in deforestation in some countries, plus increases in forest area in others through afforestation and the natural expansion of forests. A 2019 study of the global potential for tree restoration showed that there is space for at least 9 million km2 of new forests worldwide, which is a 25% increase from current conditions. This forested area could store ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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