|
Clastic Wedge
In geology, a clastic wedge is a thick accumulation of sediments or sedimentary rocks eroded and deposited landward of a mountain chain or geological boundary. They begin at the mountain front, thicken considerably landwards of it to a peak depth, and progressively thin with increasing distance inland. As they are often lens-shaped in profile, the process by which these sedimentary wedges are shaped is due to the regressive and transgressive movement from bodies of water. Some examples of clastic wedges in the United States are the Catskill Delta in Appalachia and the sequence of Jurassic and Cretaceous sediments deposited in the Cordilleran foreland basin in the Rocky Mountains.Stanley, Steven M. ''Earth System History.'' New York: W.H. Freeman and Company, 1999. pp. 243, 489 Associations Not all clastic wedges are associated with mountains. They are also a characteristic of passive continental margins such as the Gulf Coast; these are quiescent environments, where sediments ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Channel Edge In Sandstone (Dakota Sandstone, Lower Cretaceous; Dinosaur Ridge, Colorado, USA) 7
Channel, channels, channeling, etc., may refer to: Geography * Channel (geography), a landform consisting of the outline (banks) of the path of a narrow body of water. Australia * Channel Country, region of outback Australia in Queensland and partly in South Australia, Northern Territory and New South Wales. * Channel Highway, a regional highway in Tasmania, Australia. Europe * Channel Islands, an archipelago in the English Channel, off the French coast of Normandy * Channel Tunnel or Chunnel, a rail tunnel underneath the English Channel * English Channel, called simply "The Channel", the part of the Atlantic Ocean that separates Great Britain from northern France North America * Channel Islands of California, a chain of eight islands located in the Pacific Ocean off the coast of Southern California, United States * Channel Lake, Illinois, a census-designated place in Lake County, Illinois, United States * Channels State Forest, a state forest in Virginia, United States * Chan ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Organic Materials
Organic matter, organic material or natural organic matter is the large source of carbon-based compounds found within natural and engineered, terrestrial, and aquatic environments. It is matter composed of organic compounds that have come from the feces and remains of organisms such as plants and animals. Organic molecules can also be made by chemical reactions that do not involve life. Basic structures are created from cellulose, tannin, cutin, and lignin, along with other various proteins, lipids, and carbohydrates. Organic matter is very important in the movement of nutrients in the environment and plays a role in water retention on the surface of the planet. Formation Living organisms are composed of organic compounds. In life, they secrete or excrete organic material into their environment, shed body parts such as leaves and roots and after organisms die, their bodies are broken down by bacterial and fungal action. Larger molecules of organic matter can be formed from th ... [...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, sunlight, and biological organisms. It 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 either physical or chemical. The former involves the breakdown of rocks and soils through such mechanical effects as heat, water, ice and wind. The latter covers reactions to water, atmospheric gases and biologically produced chemicals with rocks and soils. Water is the principal agent behind both kinds, though atmospheric oxygen and carbon dioxide and the activities of biological organisms are also important. Biological chemical weathering is also called biological weathering. The materials left after the rock breaks down combine with organic material to create so ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Intrinsic
In science and engineering, an intrinsic property is a property of a specified subject that exists itself or within the subject. An extrinsic property is not essential or inherent to the subject that is being characterized. For example, mass is an intrinsic property of any physical object, whereas weight is an extrinsic property that depends on the strength of the gravitational field in which the object is placed. Applications in science and engineering In materials science, an intrinsic property is independent of how much of a material is present and is independent of the form of the material, e.g., one large piece or a collection of small particles. Intrinsic properties are dependent mainly on the fundamental chemical composition and structure of the material. Extrinsic properties are differentiated as being dependent on the presence of avoidable chemical contaminants or structural defects. In biology, intrinsic effects originate from inside an organism or cell, such as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Autogenic Succession
"Auto-" meaning self or same, and "-genic" meaning producing or causing. Autogenic succession refers to ecological succession driven by biotic factors within an ecosystem and although the mechanisms of autogenic succession have long been debated, the role of living things in shaping the progression of succession was realized early on. Presently, there is more of a consensus that the mechanisms of facilitation, tolerance, and inhibition all contribute to autogenic succession. The concept of succession is most often associated with communities of vegetation and forests, though it is applicable to a broader range of ecosystems. In contrast, allogenic succession is driven by the abiotic components of the ecosystem. How it occurs The plants themselves (biotic components) cause succession to occur. * Light captured by leaves *Production of detritus *Water and nutrient uptake *Nitrogen fixation *anthropogenic climate change These aspects lead to a gradual ecological change in a partic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Allogenic Succession
In ecology, allogenic succession is succession driven by the abiotic components of an ecosystem. In contrast, autogenic succession is driven by the biotic components of the ecosystem. An allogenic succession can be initiated in a number of ways which can include: *Volcanic eruptions *Meteor or comet strike *Flooding *Drought *Earthquakes * Non-anthropogenic climate change Allogenic succession can happen on a time scale that is proportionate with the disturbance. For example, allogenic succession that is the result of non-anthropogenic climate change can happen over thousands of years. Allogenic succession can also vary widely in spatial scale. Some disturbances, like landslides or localized floods, affect only small patches of land and initiate short-term successional processes. Others, such as glaciation or long-term tectonic shifts, can transform entire regions over millennia. Human activities are also a major source of allogenic disturbance. Anthropogenic events, like defores ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
River Delta
A river delta is a landform, archetypically triangular, created by the deposition of the sediments that are carried by the waters of a river, where the river merges with a body of slow-moving water or with a body of stagnant water. The creation of a river delta occurs at the '' river mouth'', where the river merges into an ocean, a sea, or an estuary, into a lake, a reservoir, or (more rarely) into another river that cannot carry away the sediment supplied by the feeding river. Etymologically, the term ''river delta'' derives from the triangular shape (Δ) of the uppercase Greek letter delta. In hydrology, the dimensions of a river delta are determined by the balance between the watershed processes that supply sediment and the watershed processes that redistribute, sequester, and export the supplied sediment into the receiving basin. River deltas are important in human civilization, as they are major agricultural production centers and population centers. They can provide ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Seismology
Seismology (; from Ancient Greek σεισμός (''seismós'') meaning "earthquake" and -λογία (''-logía'') meaning "study of") is the scientific study of earthquakes (or generally, quakes) and the generation and propagation of elastic waves through planetary bodies. It also includes studies of the environmental effects of earthquakes such as tsunamis; other seismic sources such as volcanoes, plate tectonics, glaciers, rivers, oceanic microseisms, and the atmosphere; and artificial processes such as explosions. Paleoseismology is a related field that uses geology to infer information regarding past earthquakes. A recording of Earth's motion as a function of time, created by a seismograph is called a seismogram. A seismologist is a scientist who works in basic or applied seismology. History Scholarly interest in earthquakes can be traced back to antiquity. Early speculations on the natural causes of earthquakes were included in the writings of Thales of Miletu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stratigraphy
Stratigraphy is a branch of geology concerned with the study of rock layers (strata) and layering (stratification). It is primarily used in the study of sedimentary and layered volcanic rocks. Stratigraphy has three related subfields: lithostratigraphy (lithologic stratigraphy), biostratigraphy (biologic stratigraphy), and chronostratigraphy (stratigraphy by age). Historical development Catholic priest Nicholas Steno established the theoretical basis for stratigraphy when he introduced the law of superposition, the principle of original horizontality and the principle of lateral continuity in a 1669 work on the fossilization of organic remains in layers of sediment. The first practical large-scale application of stratigraphy was by William Smith in the 1790s and early 19th century. Known as the "Father of English geology", Smith recognized the significance of strata or rock layering and the importance of fossil markers for correlating strata; he created the first geo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Molasse
__NOTOC__ In geology, "molasse" () are sandstones, shales and conglomerates that form as terrestrial or shallow marine deposits in front of rising mountain chains. The molasse deposits accumulate in a foreland basin, especially on top of flysch-like deposits, for example, those that left from the rising Alps, or erosion in the Himalaya. These deposits are typically the non-marine alluvial and fluvial sediments of lowlands, as compared to deep-water flysch sediments. Sedimentation stops when the orogeny stops, or when the mountains have eroded flat. Stanley, Steven M., ''Earth System History'', New York: W.H. Freeman and Company, 1999, p.243 The molasse can sometimes completely fill a foreland basin, creating a nearly flat depositional surface, that nonetheless remains a structural syncline. Molasse can be very thick near the mountain front, but usually thins out towards the interior of a craton; such massive, convex Convex or convexity may refer to: Science and techno ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Flysch
Flysch () is a sequence of sedimentary rock layers that progress from deep-water and turbidity flow deposits to shallow-water shales and sandstones. It is deposited when a deep basin forms rapidly on the continental side of a mountain building episode. Examples are found near the North American Cordillera, the Alps, the Pyrenees and the Carpathians. Sedimentological properties Flysch consists of repeated sedimentary cycles with upwards fining of the sediments. There are sometimes coarse conglomerates or breccias at the bottom of each cycle, which gradually evolve upwards into sandstone and shale/mudstone. Flysch typically consists of a sequence of shales rhythmically interbedded with thin, hard, graywacke-like sandstones. Typically the shales do not contain many fossils, while the coarser sandstones often have fractions of micas and glauconite. Tectonics In a continental collision, a subducting tectonic plate pushes on the plate above it, making the rock fold, often t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
