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Asymmetric Valley
An asymmetric valley is a valley that has steeper slopes on one side. Asymmetric valleys are azonal landforms. In high altitudes south-facing slopes are usually steeper than north-facing slopes. Large incised rivers crossing strike-slip faults can form asymmetrical valleys, as one bank of the river might be continuously being renewed while the other bank drifts away from the stationary river. A smaller river does not develop an asymmetrical valley as the whole river is offset or bent by the fault, rather than the river modifying the moving tectonic block. An example of this kind of asymmetrical valley can be found at the crossing of the Yellow River The Yellow River or Huang He (Chinese: , Standard Beijing Mandarin, Mandarin: ''Huáng hé'' ) is the second-longest river in China, after the Yangtze River, and the List of rivers by length, sixth-longest river system in the world at th ... with the Zhongwei-Tongxin fault. References {{geomorphology-stub Tectonics Val ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Valley
A valley is an elongated low area often running between Hill, hills or Mountain, mountains, which will typically contain a river or stream running from one end to the other. Most valleys are formed by erosion of the land surface by rivers or streams over a very long period. Some valleys are formed through erosion by glacier, glacial ice. These glaciers may remain present in valleys in high mountains or polar areas. At lower latitudes and altitudes, these glaciation, glacially formed valleys may have been created or enlarged during ice ages but now are ice-free and occupied by streams or rivers. In desert areas, valleys may be entirely dry or carry a watercourse only rarely. In karst, areas of limestone bedrock, dry valleys may also result from drainage now taking place cave, underground rather than at the surface. Rift valleys arise principally from tectonics, earth movements, rather than erosion. Many different types of valleys are described by geographers, using terms th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Slope
In mathematics, the slope or gradient of a line is a number that describes both the ''direction'' and the ''steepness'' of the line. Slope is often denoted by the letter ''m''; there is no clear answer to the question why the letter ''m'' is used for slope, but its earliest use in English appears in O'Brien (1844) who wrote the equation of a straight line as and it can also be found in Todhunter (1888) who wrote it as "''y'' = ''mx'' + ''c''". Slope is calculated by finding the ratio of the "vertical change" to the "horizontal change" between (any) two distinct points on a line. Sometimes the ratio is expressed as a quotient ("rise over run"), giving the same number for every two distinct points on the same line. A line that is decreasing has a negative "rise". The line may be practical – as set by a road surveyor, or in a diagram that models a road or a roof either as a description or as a plan. The ''steepness'', incline, or grade of a line is measured by the absolute ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Azonal
In geography, azonal is an adjective that refers to processes or things that are not restricted to any climate zone. It can be used to describe soils, landforms, geomorphic processes or vegetation. Volcanism and mountain-related processes are examples of azonal processes as they are largely independent of Earth's climate belts. In some climatic environments azonal geomorphologic processes may take distinct characteristics. For example, river activity is common across the globe, but in periglacial environments it causes spring floods from snowmelt, freezing and break-up cycles, and sometimes fluvio-thermal erosion In geomorphology fluvio-thermal erosion is the combined mechanical and thermal erosion of an unfrozen river or stream against ice-rich soils and sediments. The erosional process includes the thawing of ice sediments by a strong water flow and once .... See also * Climatic geomorphology References Phytogeography Geomorphology {{geomorph-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
River Incision
River incision is the narrow erosion caused by a river or stream that is far from its base level. River incision is common after tectonic uplift of the landscape. Incision by multiple rivers result in a dissected landscape, for example a dissected plateau. River incision is the natural process by which a river cuts downward into its bed, deepening the active channel. Though it is a natural process, it can be accelerated rapidly by human factors including land use changes such as timber harvest, mining, agriculture, and road and dam construction. The rate of incision is a function of basal shear-stress. Shear stress is increased by factors such as sediment in the water, which increase its density. Shear stress t is proportional to water mass, gravity, and WSS: ::t = \rho gD\sin where t is shear stress (N/m2), ρ is density of flowing water, g is gravity In physics, gravity () is a fundamental interaction which causes mutual attraction between all things with mass or energ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Strike-slip Fault
In geology, a fault is a planar fracture or discontinuity in a volume of rock across which there has been significant displacement as a result of rock-mass movements. Large faults within Earth's crust result from the action of plate tectonic forces, with the largest forming the boundaries between the plates, such as the megathrust faults of subduction zones or transform faults. Energy release associated with rapid movement on active faults is the cause of most earthquakes. Faults may also displace slowly, by aseismic creep. A ''fault plane'' is the plane that represents the fracture surface of a fault. A ''fault trace'' or ''fault line'' is a place where the fault can be seen or mapped on the surface. A fault trace is also the line commonly plotted on geologic maps to represent a fault. A ''fault zone'' is a cluster of parallel faults. However, the term is also used for the zone of crushed rock along a single fault. Prolonged motion along closely spaced faults can blur the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Yellow River
The Yellow River or Huang He (Chinese: , Standard Beijing Mandarin, Mandarin: ''Huáng hé'' ) is the second-longest river in China, after the Yangtze River, and the List of rivers by length, sixth-longest river system in the world at the estimated length of . Originating in the Bayan Har Mountains in Qinghai province of Western China, it flows through nine provinces, and it empties into the Bohai Sea near the city of Dongying in Shandong province. The Yellow River basin has an east–west extent of about and a north–south extent of about . Its total drainage area is about . The Yellow River's basin was the Yellow River civilization, birthplace of ancient Chinese, and, by extension, Far East, Far Eastern civilization, and it was the most prosperous region in early Chinese history. There are frequent devastating natural disasters in China, floods and course changes produced by the continual elevation of the river bed, sometimes above the level of its surrounding farm fi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Zhongwei-Tongxin Fault
The Zhongwei-Tongxin fault or Tianjingshan fault is an arcuate sinistral (left-lateral) strike-slip zone, forming one of the major structures on the northeastern margin of Tibetan plateau. Six paleoearthquake events in the past 14,000 years have been recorded along the Zhongwei-Tongxin fault zone. Among the earthquakes recorded are the 1622 North Guyuan earthquake, which had a magnitude of 7.0 and mid-seismogenic depth of about , the 1709 Zhongwei earthquake, which had a magnitude of 7.5. Tectonic setting The Zhongwei-Tongxin fault is one of the structures that accommodates the eastward spreading of the thickened crust of the Tibetan Plateau, the result of the ongoing collision between the Indian Plate and the Eurasian Plate. The northeastern margin of the Tibetan Plateau is marked by a combination of sinistral (left-lateral) strike-slip faults and thrust faults. The largest of the strike-slip faults is the 1,000 km long WNW–ESE trending Haiyan fault, which links to the east w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Quaternary Research
''Quaternary Research'' is a peer-reviewed scientific journal of Quaternary science. The journal was established in 1970, is now published by Cambridge University Press, and is edited by Derek B. Booth, Nicholas Lancaster and Lewis A. Owen. Previous editors included A. Lincoln Washburn, Estella B. Leopold, Stephen C. Porter, Eric J. Steig, and Alan R. Gillespie. Abstracting and indexing The journal is abstracted and Indexed by: CABI, British and Irish Archaeological Bibliography, EBSCO, GEOBASE, Scopus, Gale, International Atomic Energy Agency, PubMed, Ovid, ProQuest, Web of Science, GeoRefIts. The latest impact factor The impact factor (IF) or journal impact factor (JIF) of an academic journal is a scientometric index calculated by Clarivate that reflects the yearly mean number of citations of articles published in the last two years in a given journal, as i ... (2015) was 2.198. External links * Quaternary science journals Cambridge University Press academic j ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tectonics
Tectonics (; ) are the processes that control the structure and properties of the Earth's crust and its evolution through time. These include the processes of mountain building, the growth and behavior of the strong, old cores of continents known as cratons, and the ways in which the relatively rigid plates that constitute the Earth's outer shell interact with each other. Tectonics also provide a framework for understanding the earthquake and volcanic belts that directly affect much of the global population. Tectonic studies are important as guides for economic geologists searching for fossil fuels and ore deposits of metallic and nonmetallic resources. An understanding of tectonic principles is essential to geomorphologists to explain erosion patterns and other Earth surface features. Main types of tectonic regime Extensional tectonics Extensional tectonics is associated with the stretching and thinning of the crust or the lithosphere. This type of tectonics is found ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
