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Windstreak
A windstreak is a planetary surface feature of aeolian origin characterized by an albedo that contrasts with surrounding surface in an elongated pattern. Windstreaks are associated with topographical obstacles, and are very commonly, but not exclusively, found near craters. These features have been observed on Mars, Venus, Titan, and the Earth, although they are considered rare on Earth. Terrestrial examples of windstreaks are found at the Pali-Aike volcanic field. Windstreaks are a term that is more used in remote sensing, as such an albedo pattern can be representative of many geomorphological features, albeit all of an aeolian origin. All forms of sediment transport ( saltation, traction, and suspension) and sediment sizes ( clay to gravel Gravel is a loose aggregation of rock fragments. Gravel occurs naturally throughout the world as a result of sedimentary and erosive geologic processes; it is also produced in large quantities commercially as crushed stone. Gravel ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Windstreak
A windstreak is a planetary surface feature of aeolian origin characterized by an albedo that contrasts with surrounding surface in an elongated pattern. Windstreaks are associated with topographical obstacles, and are very commonly, but not exclusively, found near craters. These features have been observed on Mars, Venus, Titan, and the Earth, although they are considered rare on Earth. Terrestrial examples of windstreaks are found at the Pali-Aike volcanic field. Windstreaks are a term that is more used in remote sensing, as such an albedo pattern can be representative of many geomorphological features, albeit all of an aeolian origin. All forms of sediment transport ( saltation, traction, and suspension) and sediment sizes ( clay to gravel Gravel is a loose aggregation of rock fragments. Gravel occurs naturally throughout the world as a result of sedimentary and erosive geologic processes; it is also produced in large quantities commercially as crushed stone. Gravel ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pali-Aike Volcanic Field
The Pali-Aike volcanic field is a volcanic field along the Argentina–Chile border. It is part of a family of back-arc volcanoes in Patagonia, which formed from processes involving the collision of the Chile Ridge with the Peru–Chile Trench. It lies farther east than the Austral Volcanic Zone, the volcanic arc that makes up the Andean Volcanic Belt at this latitude. Pali-Aike formed over sedimentary rock of Magallanes Basin, a Jurassic-age basin starting from the late Miocene as a consequence of regional tectonic events. The volcanic field consists of an older plateau basalt formation and younger volcanic centres in the form of pyroclastic cones, scoria cones, maars and associated lava flows. There are approximately 467 vents in an area of . The vents often form local alignments along lineaments or faults, and there are a number of maars and other lakes, both volcanic and non-volcanic. The volcanic field is noteworthy for the presence of large amounts of xenoliths in its ro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aeolian Landform
Aeolian landforms are features produced by either the erosive or constructive action of the wind. These features may be built up from sand or snow, or eroded into rock, snow, or ice. Aeolian landforms are commonly observed in sandy deserts and on frozen lakes or sea ice and have been observed and studied across Earth and on other planets, including Mars and Pluto Terminology The word "aeolian" derives from Æolus, the Greek god of the winds, and the son of Hellen and the nymph Orseis, and a brother of Dorus, Xuthus and Amphictyon. Mechanisms Aeolian landforms are formed when wind moves sediment (see aeolian processes). Sediment particles move when they are lifted by upwards Bernoulli forces that exceed their downwards weight or when they are dragged from their initial position. Depending on the balance of these forces, particles may either creep (roll) across the surface until they settle due to a loss of velocity; hop from point to point; or be suspended entirely in the air. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Albedo
Albedo (; ) is the measure of the diffuse reflection of sunlight, solar radiation out of the total solar radiation and measured on a scale from 0, corresponding to a black body that absorbs all incident radiation, to 1, corresponding to a body that reflects all incident radiation. Surface albedo is defined as the ratio of Radiosity (radiometry), radiosity ''J''e to the irradiance ''E''e (flux per unit area) received by a surface. The proportion reflected is not only determined by properties of the surface itself, but also by the spectral and angular distribution of solar radiation reaching the Earth's surface. These factors vary with atmospheric composition, geographic location, and time (see position of the Sun). While bi-hemispherical reflectance is calculated for a single angle of incidence (i.e., for a given position of the Sun), albedo is the directional integration of reflectance over all solar angles in a given period. The temporal resolution may range from seconds (as ob ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Icarus (journal)
''ICARUS'' is a scientific journal dedicated to the field of planetary science. It is officially endorsed by the American Astronomical Society's Division for Planetary Sciences (DPS). The journal contains articles discussing the results of new research on astronomy, geology, meteorology, physics, chemistry, biology, and other scientific aspects of the Solar System or extrasolar systems. The journal was founded in 1962, and became affiliated with the DPS in 1974. Its original owner and publisher was Academic Press, which was purchased by Elsevier in 2000. The journal is named for the mythical Icarus, and the frontispiece of every issue contains an extended quotation from Sir Arthur Eddington equating Icarus' adventurousness with the scientific investigator who "strains his theories to the breaking-point till the weak joints gape." Abstracting and indexing This journal is indexed by the following services: * Science Citation Index * Current Contents /Physical, Chemical & E ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Titan (moon)
Titan is the largest moon of Saturn and the second-largest natural satellite in the Solar System. It is the only moon known to have a dense atmosphere, and is the only known object in space other than Earth on which clear evidence of stable bodies of surface liquid has been found. Titan is one of the seven gravitationally rounded moons in orbit around Saturn, and the second most distant from Saturn of those seven. Frequently described as a planet-like moon, Titan is 50% larger (in diameter) than Earth's Moon and 80% more massive. It is the second-largest moon in the Solar System after Jupiter's moon Ganymede, and is larger than the planet Mercury, but only 40% as massive. Discovered in 1655 by the Dutch astronomer Christiaan Huygens, Titan was the first known moon of Saturn, and the sixth known planetary satellite (after Earth's moon and the four Galilean moons of Jupiter). Titan orbits Saturn at 20 Saturn radii. From Titan's surface, Saturn subtends an arc of 5.09 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Remote Sensing
Remote sensing is the acquisition of information about an object or phenomenon without making physical contact with the object, in contrast to in situ or on-site observation. The term is applied especially to acquiring information about Earth and other planets. Remote sensing is used in numerous fields, including geography, land surveying and most Earth science disciplines (e.g. hydrology, ecology, meteorology, oceanography, glaciology, geology); it also has military, intelligence, commercial, economic, planning, and humanitarian applications, among others. In current usage, the term ''remote sensing'' generally refers to the use of satellite- or aircraft-based sensor technologies to detect and classify objects on Earth. It includes the surface and the atmosphere and oceans, based on propagated signals (e.g. electromagnetic radiation). It may be split into "active" remote sensing (when a signal is emitted by a satellite or aircraft to the object and its reflection detected by ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geomorphology
Geomorphology (from Ancient Greek: , ', "earth"; , ', "form"; and , ', "study") is the scientific study of the origin and evolution of topographic and bathymetric features created by physical, chemical or biological processes operating at or near Earth's surface. Geomorphologists seek to understand why landscapes look the way they do, to understand landform and terrain history and dynamics and to predict changes through a combination of field observations, physical experiments and numerical modeling. Geomorphologists work within disciplines such as physical geography, geology, geodesy, engineering geology, archaeology, climatology, and geotechnical engineering. This broad base of interests contributes to many research styles and interests within the field. Overview Earth's surface is modified by a combination of surface processes that shape landscapes, and geologic processes that cause tectonic uplift and subsidence, and shape the coastal geography. Surface processes co ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Saltation (geology)
In geology, saltation () is a specific type of particle transport by fluids such as wind or water. It occurs when loose materials are removed from a bed and carried by the fluid, before being transported back to the surface. Examples include pebble transport by rivers, sand drift over desert surfaces, soil blowing over fields, and snow drift over smooth surfaces such as those in the Arctic or Canadian Prairies. Process At low fluid velocities, loose material rolls downstream, staying in contact with the surface. This is called ''creep'' or ''reptation''. Here the forces exerted by the fluid on the particle are only enough to roll the particle around the point of contact with the surface. Once the wind speed reaches a certain critical value, termed the ''impact'' or ''fluid threshold'', the drag and lift forces exerted by the fluid are sufficient to lift some particles from the surface. These particles are accelerated by the fluid, and pulled downward by gravity, causing them to t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Traction (geology)
Traction is the geologic process whereby a current transports larger, heavier rocks by rolling or sliding them along the bottom. Thus, the grains and clasts interact with the substratum during transport. By contrast, saltation, a related sediment transport process, moves grains across the bottom by bouncing or hopping. The actual current carries the sediment load in traction and saltation flows, whereas downslope movement under the force of gravity carries the sediment in gravity flows. These processes contrast with suspension settling, in which there is no current.Ritter, M.E. (2006), The Physical Environment: an Introduction to Physical Geography: The Geologic Work of Streams,'' online textbook. accessed 25 June 2013. Traction is where large stones or boulders in the river's load are rolled along by the force of the river. Notes and references External links How a river's load is transported by traction - Geography animated {{geology-stub Sedimentology ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Suspension (geology)
Suspension or suspended may refer to: Science and engineering * Suspension (topology), in mathematics * Suspension (dynamical systems), in mathematics * Suspension of a ring, in mathematics * Suspension (chemistry), small solid particles suspended in a liquid **Colloidal suspension * Cell suspension or suspension culture, in biology * Suspension (mechanics), system allowing a machine to move smoothly with reduced shock * The superstructure of a suspension bridge * Suspensory behavior, arboreal locomotion of primates * Magnetic suspension, a method by which an object is suspended with no support other than magnetic fields * Car suspension Temporary revocation of privileges * Suspension (punishment), temporary exclusion as a punishment ** Suspension from the UK parliament ** Suspension (Catholic canonical penalty) * Suspension of driving privileges ("suspended driver's license") * Administrative License Suspension (ALS), US, driving license suspension without a court hearing ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Clay
Clay is a type of fine-grained natural soil material containing clay minerals (hydrous aluminium phyllosilicates, e.g. kaolin, Al2 Si2 O5( OH)4). Clays develop plasticity when wet, due to a molecular film of water surrounding the clay particles, but become hard, brittle and non–plastic upon drying or firing. Most pure clay minerals are white or light-coloured, but natural clays show a variety of colours from impurities, such as a reddish or brownish colour from small amounts of iron oxide. Clay is the oldest known ceramic material. Prehistoric humans discovered the useful properties of clay and used it for making pottery. Some of the earliest pottery shards have been dated to around 14,000 BC, and clay tablets were the first known writing medium. Clay is used in many modern industrial processes, such as paper making, cement production, and chemical filtering. Between one-half and two-thirds of the world's population live or work in buildings made with clay, often ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
