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Offlap
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 short of the full extent of the underlying older bed, typically due to a marine regression A marine regression is a geological process occurring when areas of submerged seafloor are exposed during a drop in sea level. The opposite event, marine transgression, occurs when flooding from the sea covers previously-exposed land. Descript .... References Stratigraphy {{stratigraphy-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geological
Geology (). is a branch of natural science concerned with the Earth and other astronomical objects, the rocks of which they are composed, and the processes by which they change over time. Modern geology significantly overlaps all other Earth sciences, including hydrology. It is integrated with 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. Geologists study the mineralogical composition of rocks in order to get insight into their history of formation. Geology determines the relative ages of rocks found at a given location; geochemistry (a branch of geology) determines their Geochronology, absolute ages. By combining various petrological, crystallographic, and paleontological tools, geologists are able to chronicle the geological history of the Earth as a whole. One aspect is to demonstrate the age of the Earth. Geology provides evidence for plate tectonics, the ... [...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 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] |
Erosion Surface
In geology and geomorphology, an erosion surface is a surface of rock (geology), rock or regolith that was formed by erosion and not by construction (e.g. lava flows, sediment deposition) nor fault (geology), fault displacement. Erosional surfaces within the Lithostratigraphy#Stratigraphic relationship, stratigraphic record are known as unconformity, unconformities, but not all unconformities are buried erosion surfaces. Erosion surfaces vary in scale and can be formed on a mountain range or a rock. Particularly large and flat erosion surfaces receive the names of peneplain, wikt:paleoplain, paleoplain, planation surface or pediplain. An example of erosion surface is road surface erosion which is caused by natural and anthropogenic factors. Erosion surface can be measured through direct, contact measurement methods and indirect, non-contact measurement methods. Road surface erosion Just like mountains and rocks, erosion can also occur on unsealed roads due to natural and Human im ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Marine Transgression
A marine transgression is a geologic event where sea level rises relative to the land and the shoreline moves toward higher ground, resulting in flooding. Transgressions can be caused by the land sinking or by the ocean basins filling with water or decreasing in capacity. Transgressions and regressions may be caused by tectonic events like orogenies, severe climate change such as ice ages or isostatic adjustments following removal of ice or sediment load. During the Cretaceous, seafloor spreading created a relatively shallow Atlantic basin at the expense of a deeper Pacific basin. That reduced the world's ocean basin capacity and caused a rise in sea level worldwide. As a result of the sea level rise, the oceans transgressed completely across the central portion of North America and created the Western Interior Seaway from the Gulf of Mexico to the Arctic Ocean. The opposite of transgression is regression where the sea level falls relative to the land and exposes the form ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 Indira Gandhi National Open University (IGNOU) is a National university, public Open university (concept), open & Distance education, distance learning university located in Delhi, India. Named after the former Prime Minister of India, prime ... 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). ''BG ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pinches Out
Pinches is the surname of the following people: * Barry Pinches (born 1970), English snooker player * Jennifer Pinches (born 1994), British artistic gymnast *John Pinches John Harvey Pinches (9 April 1916 – 2 July 2007) was an English rowing (sport), rower, Royal Engineers officer, medallist and author. Pinches was born at Chelsea, London, the son of John Robert Pinches and Irene Inchbold. His father was a meda ... (1916–2007), English rower, Royal Engineers officer, medallist and author * Theophilus Pinches (1856–1934), British assyriologist See also * Pincher (other) {{surname English-language surnames ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Marine Regression
A marine regression is a geological process occurring when areas of submerged seafloor are exposed during a drop in sea level. The opposite event, marine transgression, occurs when flooding from the sea covers previously-exposed land. Description According to one hypothesis, regressions may be linked to a "slowdown in sea-floor spreading, leading to a generalized drop in sea level (as the mid-ocean ridges would take up less space)...." That view considers major marine regressions to be one aspect of a normal variation in rates of plate tectonic activity, which leads to major episodes of global volcanism like the Siberian Traps and the Deccan Traps, which in turn cause large extinction events. Evidence of marine regressions and transgressions occurs throughout the fossil record, and the fluctuations are thought to have caused or contributed to several mass extinctions, such as the Permian–Triassic extinction event (250 million years ago, Ma) and Cretaceous–Paleogene ex ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
