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Overstep
An overstep is a geological form that has a deposition of a stratum across inclined, progressively older rocks.Alistair F. Pitty ''Structure and Relief'' 1985 Page 28 "An overstep is a geological term describing the deposition of a stratum across inclined, progressively older rocks, as seen on both flanks of the Market Weighton axis (figure 9). In South East England, the Lower Greensand is another very ..." The Indira Gandhi National Open University syllabus definition is: "The term ''overstep'' is used to describe the relationship of beds in an unconformable sequence where the younger series rests upon progressively older members of the underlying series."Indira Gandhi National Open University (School of Sciences), (Undated). ''BGYCT-131 - Physical And Structural Geology, Block 3 - Structural Geology, Unit 12 - Joints And Unconformities''. egyankosh.ac.inArchived An onlap Onlap or ''overlap'' is the geological phenomenon of successively wedge-shaped younger rock strata extendin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geological
Geology () is a branch of natural science concerned with Earth and other astronomical objects, the features or rocks of which it is composed, and the processes by which they change over time. Modern geology significantly overlaps all other Earth sciences, including hydrology, and so is treated as one major aspect of integrated Earth system science and planetary science. Geology describes the structure of the Earth on and beneath its surface, and the processes that have shaped that structure. It also provides tools to determine the relative and absolute ages of rocks found in a given location, and also to describe the histories of those rocks. By combining these tools, geologists are able to chronicle the geological history of the Earth as a whole, and also to demonstrate the age of the Earth. Geology provides the primary evidence for plate tectonics, the evolutionary history of life, and the Earth's past climates. Geologists broadly study the properties and processes of Ear ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Deposition (geology)
Deposition is the geological process in which sediments, soil and rocks are added to a landform or landmass. Wind, ice, water, and gravity transport previously weathered surface material, which, at the loss of enough kinetic energy in the fluid, is deposited, building up layers of sediment. Deposition occurs when the forces responsible for sediment transportation are no longer sufficient to overcome the forces of gravity and friction, creating a resistance to motion; this is known as the null-point hypothesis. Deposition can also refer to the buildup of sediment from organically derived matter or chemical processes. For example, chalk is made up partly of the microscopic calcium carbonate skeletons of marine plankton, the deposition of which has induced chemical processes (diagenesis) to deposit further calcium carbonate. Similarly, the formation of coal begins with the deposition of organic material, mainly from plants, in anaerobic conditions. Null-point hypothesis The null ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stratum
In geology and related fields, a stratum ( : strata) is a layer of rock or sediment characterized by certain lithologic properties or attributes that distinguish it from adjacent layers from which it is separated by visible surfaces known as either '' bedding surfaces'' or ''bedding planes''.Salvador, A. ed., 1994. ''International stratigraphic guide: a guide to stratigraphic classification, terminology, and procedure. 2nd ed.'' Boulder, Colorado, The Geological Society of America, Inc., 215 pp. . Prior to the publication of the International Stratigraphic Guide, older publications have defined a stratum as either being either equivalent to a single bed or composed of a number of beds; as a layer greater than 1 cm in thickness and constituting a part of a bed; or a general term that includes both ''bed'' and ''lamina''.Neuendorf, K.K.E., Mehl, Jr., J.P., and Jackson, J.A. , eds., 2005. ''Glossary of Geology'' 5th ed. Alexandria, Virginia, American Geological Institute. 779 pp. . ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Market Weighton Axis
The Market Weighton Axis is a geological feature which forms the south-eastern part of Yorkshire, England. The feature goes under a number of names such as 'block' or 'area' while the name of the town, Market Weighton is retained. 'Block' seems to be the most modern version but the most distinctive and widely known is 'axis'. It takes the form of a ridge of tectonic uplift which has progressed during the period of deposition of the newer rocks from at least the end of the Triassic (205 million years ago) onwards. Its uplift has more or less kept pace with the deposition so that on the north and south sides of it, each stratum thins to nothing and in most cases, picks up again on the other side. During the Carboniferous, the relationship between the Market Weighton Axis and the London-Brabant Massif affected the weaker rocks between them so influencing the geography at the surface. Features in the intervening district were the Widmerpool Gulf and the equatorial swamps which led to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
South East England
South East England is one of the nine official regions of England at the ITL 1 statistical regions of England, first level of International Territorial Level, ITL for Statistics, statistical purposes. It consists of the counties of england, counties of Buckinghamshire, East Sussex, Hampshire, the Isle of Wight, Kent, Oxfordshire, Berkshire, Surrey and West Sussex. Major towns and cities in the region include Brighton and Hove, Milton Keynes, Southampton, Portsmouth, Slough, Reading, Berkshire, Reading and Oxford. South East England is the third largest region of England, with an area of 19,096 km2 (7,373 sq mi), and is also the most populous with a total population of over eight and a half million (2011). The region contains seven legally city status in the United Kingdom, chartered cities: Brighton and Hove, Canterbury, Chichester, Oxford, Portsmouth, Southampton and Winchester. The region's close proximity to London and connections to several national motorways have le ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Greensand
Greensand or green sand is a sand or sandstone which has a greenish color. This term is specifically applied to shallow marine sediment that contains noticeable quantities of rounded greenish grains. These grains are called ''glauconies'' and consist of a mixture of mixed-layer clay minerals, such as smectite and glauconite. Greensand is also loosely applied to any glauconitic sediment. Formation Greensand forms in anoxic marine environments that are rich in organic detritus and low in sedimentary input. Having accumulated in marine environments, greensands can be fossil-rich, such as in the late-Cretaceous deposits of New Jersey. Occurrence Important exposures are known from both northern and western Europe, North America, southeastern Brazil and north Africa. Well known and important greensands are the Upper and Lower Greensands of England and occur within Eocene and Cretaceous sedimentary strata underlying the coastal plains of New Jersey and Delaware. Although greensand h ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Indira Gandhi National Open University
Indira Gandhi National Open University, known as IGNOU, is a Central University located at Maidan Garhi, New Delhi, India. Named after former Prime Minister of India Indira Gandhi, the university was established in 1985 with a budget of 20 million, after the Parliament of India passed the ''Indira Gandhi National Open University Act, 1985'' (IGNOU Act 1985). IGNOU is run by the central government of India, and with total active enrollment of over 4 million students, it is the largest university in the world. IGNOU was founded to serve the Indian population by means of distance and open education, providing quality higher education opportunities to all segments of society. It also aims to encourage, coordinate and set standards for distance and open education in India, and to strengthen the human resources of India through education. Apart from teaching and research, extension and training form the mainstay of its academic activities. It also acts as a national resourc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Onlap
Onlap or ''overlap'' is the geological phenomenon of successively wedge-shaped younger rock strata extending progressively further across an erosion surface cut in older rocks. It is generally associated with a marine transgression. It is a more general term than ''overstep'', in which the younger beds overlap onto successively older beds. The opposite is offlap, in which each younger rock bed pinches out A pinch-out or wedge-out is a point where a stratum or other lithologically distinct body of rock thins to a feather edge and disappears, so that the underlying and overlying strata separated by the pinching out stratum come into direct contact. T ... short of the full extent of the underlying older bed, typically due to a marine regression. References Stratigraphy {{Geology-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
