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Lavaka
Lavaka ({{IPA-mg, ˈlavakə̥), the Malagasy word for "hole", usually found on the side of a hill, is a type of erosional feature common in Madagascar. However, lavakas have also been found in South Africa, the Democratic Republic of the Congo, and South Carolina, and similar landforms have been found in Brazil, the Great Plains of the U.S., and Eswatini. They are most common in tropical regions between the Cancer and Capricorn latitudes, especially the Central Highlands of Madagascar, where approximately one metre thick laterites develop on steep terrains in a monsoonal climate. Lavakas form where these hard laterites overlie thick (tens of metres) saprolite, on steep (35 to 55 degree) slopes, in areas that have a hot dry season and a warm wet season. Lavakas are not landslides. They are a type of gully, formed via groundwater sapping. They are usually shaped like a tear-drop with a steep, round headwall that narrows downhill into a shallow outlet channel. Although human a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Groundwater Sapping
Groundwater sapping is a geomorphic erosion process that results in the headward migration of channels in response to near constant fluid discharge at a fixed point. The consistent flow of water displaces fine sediments which physically and chemically weathers rocks. Valleys that appear to have been created by groundwater sapping occur throughout the world in areas such as England, Colorado, Hawai’i, New Zealand, and many other places. However, it is difficult to characterize a landform as being formed exclusively by groundwater sapping due to phenomena such as pluvial runoff, plunge-pool undercutting, changes in water table level, and inconsistent groundwater flow. An example of drainage ways created purely by the outflow of subsurface fluids can be seen on the foreshores of beaches. As the surge of water and sand brought to land by a wave retreats seaward, the film of water becomes thinner until it forms rhomboid shaped patterns in the sand. Small fans form at the apex of the rhom ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lavaca (other) , a type of hole caused by erosion of hillsides
{{disambiguation ...
Lavaca may stand for: *Lavaca, Arkansas *Lavaca County, Texas *Lavaca River *Port Lavaca, Texas *Lavaca Bay See also * la Vaca (other) * ''Lavaka'', a Tongan nobility title, see Tupou VI * Lavaka Lavaka ({{IPA-mg, ˈlavakə̥), the Malagasy word for "hole", usually found on the side of a hill, is a type of erosional feature common in Madagascar. However, lavakas have also been found in South Africa, the Democratic Republic of the Congo, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Landforms Of Madagascar
A landform is a natural or anthropogenic land feature on the solid surface of the Earth or other planetary body. Landforms together make up a given terrain, and their arrangement in the landscape is known as topography. Landforms include hills, mountains, canyons, and valleys, as well as shoreline features such as bays, peninsulas, and seas, including submerged features such as mid-ocean ridges, volcanoes, and the great ocean basins. Physical characteristics Landforms are categorized by characteristic physical attributes such as elevation, slope, orientation, stratification, rock exposure and soil type. Gross physical features or landforms include intuitive elements such as berms, mounds, hills, ridges, cliffs, valleys, rivers, peninsulas, volcanoes, and numerous other structural and size-scaled (e.g. ponds vs. lakes, hills vs. mountains) elements including various kinds of inland and oceanic waterbodies and sub-surface features. Mountains, hills, plateaux, and plains are the fo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geomorphology (journal)
''Geomorphology'' is a peer-reviewed scientific journal about 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 n .... External links * Earth and atmospheric sciences journals Elsevier academic journals English-language journals Geomorphology journals {{Geomorphology-journal-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Earth Surface Processes And Landforms
''Earth Surface Processes and Landforms'' is a peer-reviewed scientific journal published by John Wiley & Sons on behalf of the British Society for Geomorphology. It covers geomorphology and more in general all aspects of Earth sciences dealing with the Earth surface. The journal was established in 1976 as ''Earth Surface Processes'', obtaining its current name in 1981. The journal primarily publishes original research papers. It also publishes ''Earth Surface Exchanges'' which include commentaries on issues of particular geomorphological interest, discussions of published papers, shorter journal articles suitable for rapid publication, and commissioned reviews on key aspects of geomorphological science. Foci include the physical geography of rivers, valleys, glaciers, mountains, hills, slopes, coasts, deserts, and estuary environments, along with research into Holocene, Pleistocene, or Quaternary science. The editor-in-chief is Stuart Lane (University of Lausanne). Abstracting and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
South African Journal Of Geology
The ''South African Journal of Geology'' is a quarterly peer-reviewed scientific journal published by the Geological Society of South Africa that was established in March 1896 as the ''Transactions of the Geological Society of South Africa'', obtaining its current title in 1987. Incorporated into the volumes up to and including volume 73 (1970) were the ''Proceedings of the Geological Society of South Africa''. The journal publishes scientific papers, notes, stratigraphic descriptions, and discussions in the broadly defined fields of geoscience that are related directly or indirectly to the geology of Africa. Contributions relevant to former supercontinents such as Gondwana and Pangaea are also published as are topical studies on any geology-related discipline. GSSA Publications. Retrieved 01 June 2019. The journal is |
Rónadh Cox
Rónadh Cox (born 1962) is an Irish geologist who is the Edward Brust Professor of Geology and Mineralogy at Williams College, Massachusetts. Her research considers the impact of storms on coastal boulders. She is a Fellow of the Geological Society of America and Future Earth Costs. Early life and education Cox is from Ireland. She says she became interested in geology as a teenager, because her geography teacher "delighted in the natural world,". She attended University College Dublin for her undergraduate degree, where she majored in geology. After earning her bachelor's degree, Cox moved to BP, where she worked as a geological assistant. She moved to the United States for her graduate research, joining Stanford University as a doctoral student. After earning her doctorate, Cox was appointed to the Rand Afrikaans University as a postdoctoral researcher. She spent two years in South Africa before returning to North America. Research and career Cox joined the faculty at Willia ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Leaching (agriculture)
In agriculture, leaching is the loss of water-soluble plant nutrients from the soil, due to rain and irrigation. Soil structure, crop planting, type and application rates of fertilizers, and other factors are taken into account to avoid excessive nutrient loss. Leaching may also refer to the practice of applying a small amount of excess irrigation where the water has a high salt content to avoid salts from building up in the soil (salinity control). Where this is practiced, drainage must also usually be employed, to carry away the excess water. Leaching is a natural environment concern when it contributes to groundwater contamination. As water from rain, flooding, or other sources seeps into the ground, it can dissolve chemicals and carry them into the underground water supply. Of particular concern are hazardous waste dumps and landfills, and, in agriculture, excess fertilizer, improperly stored animal manure, and biocides (e.g. pesticides, fungicides, insecticides and herb ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Topographic Relief
Terrain or relief (also topographical relief) involves the vertical and horizontal dimensions of land surface. The term bathymetry is used to describe underwater relief, while hypsometry studies terrain relative to sea level. The Latin word (the root of ''terrain'') means "earth." In physical geography, terrain is the lay of the land. This is usually expressed in terms of the elevation, slope, and orientation of terrain features. Terrain affects surface water flow and distribution. Over a large area, it can affect weather and climate patterns. Importance The understanding of terrain is critical for many reasons: * The terrain of a region largely determines its suitability for human settlement: flatter alluvial plains tend to have better farming soils than steeper, rockier uplands. * In terms of environmental quality, agriculture, hydrology and other interdisciplinary sciences; understanding the terrain of an area assists the understanding of watershed boundaries, drai ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Seismic Activity
An earthquake (also known as a quake, tremor or temblor) is the shaking of the surface of the Earth resulting from a sudden release of energy in the Earth's lithosphere that creates seismic waves. Earthquakes can range in intensity, from those that are so weak that they cannot be felt, to those violent enough to propel objects and people into the air, damage critical infrastructure, and wreak destruction across entire cities. The seismic activity of an area is the frequency, type, and size of earthquakes experienced over a particular time period. The seismicity at a particular location in the Earth is the average rate of seismic energy release per unit volume. The word ''tremor'' is also used for non-earthquake seismic rumbling. At the Earth's surface, earthquakes manifest themselves by shaking and displacing or disrupting the ground. When the epicenter of a large earthquake is located offshore, the seabed may be displaced sufficiently to cause a tsunami. Earthquakes ca ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Radiocarbon Dating
Radiocarbon dating (also referred to as carbon dating or carbon-14 dating) is a method for determining the age of an object containing organic material by using the properties of radiocarbon, a radioactive isotope of carbon. The method was developed in the late 1940s at the University of Chicago by Willard Libby. It is based on the fact that radiocarbon () is constantly being created in the Earth's atmosphere by the interaction of cosmic rays with atmospheric nitrogen. The resulting combines with atmospheric oxygen to form radioactive carbon dioxide, which is incorporated into plants by photosynthesis; animals then acquire by eating the plants. When the animal or plant dies, it stops exchanging carbon with its environment, and thereafter the amount of it contains begins to decrease as the undergoes radioactive decay. Measuring the amount of in a sample from a dead plant or animal, such as a piece of wood or a fragment of bone, provides information that can be used to calc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Overgrazing
Overgrazing occurs when plants are exposed to intensive grazing for extended periods of time, or without sufficient recovery periods. It can be caused by either livestock in poorly managed agricultural applications, game reserves, or nature reserves. It can also be caused by immobile, travel restricted populations of native or non-native wild animals. Overgrazing reduces the usefulness, productivity, and biodiversity of the land and is one cause of desertification and erosion. Overgrazing is also seen as a cause of the spread of invasive species of non-native plants and of weeds. Degrading land, emissions from animal agriculture and reducing the biomass in a ecosystem contribute directly to climate change. Overgrazing can be reversed or prevented by removing grazers in order to give plants time to recover between grazing events. Successful planned grazing strategies have been support in the American bison of the Great Plains, or migratory Wildebeests of the African savann ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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