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Soft-sediment Deformation Structures
{{Short description, Geologic formation Soft-sediment deformation structures develop at deposition or shortly after, during the first stages of the sediment's consolidation. This is because the sediments need to be "liquid-like" or unsolidified for the deformation to occur. These formations have also been put into a category called water-escape structures by Lowe (1975). The most common places for soft-sediment deformations to materialize are in deep water basins with turbidity currents, rivers, deltas, and shallow-marine areas with storm impacted conditions. This is because these environments have high deposition rates, which allows the sediments to pack loosely. Types of soft-sediment deformation structures *Convolute bedding forms when complex folding and crumpling of beds or laminations occur. This type of deformation is found in fine or silty sands, and is usually confined to one rock layer. Convolute laminations are found in flood plain, delta, point-bar, and intertidal-fl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Soft Sed Deformation Mcr1
Soft may refer to: * Softness, or hardness, a property of physical materials Arts and entertainment * ''Soft!'', a 1988 novel by Rupert Thomson * Soft (band), an American music group * ''Soft'' (album), by Dan Bodan, 2014 * Softs (album), by Soft Machine, 1976 * "Soft", a song by Kings of Leon on the 2004 album ''Aha Shake Heartbreak'' * "Soft"/"Rock", a 2001 single by Lemon Jelly Other uses * Sorgenti di Firenze Trekking (SOFT), a system of walking trails in Italy * Soft matter, a subfield of condensed matter * Magnetically soft, material with low coercivity * Soft skills, a person's people, social, and other skills * Soft commodities, or softs *A flaccid penis Tumescence is the quality or state of being tumescent or swollen. Tumescence usually refers to the normal engorgement with blood (vascular congestion) of the erectile tissues, marking sexual excitation, and possible readiness for sexual activity. ..., the opposite of "hard" See also * * * Softener (disambiguation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Soft Sed Deformation Turbidites
Soft may refer to: * Softness, or hardness, a property of physical materials Arts and entertainment * ''Soft!'', a 1988 novel by Rupert Thomson * Soft (band), an American music group * ''Soft'' (album), by Dan Bodan, 2014 * Softs (album), by Soft Machine, 1976 * "Soft", a song by Kings of Leon on the 2004 album ''Aha Shake Heartbreak'' * "Soft"/"Rock", a 2001 single by Lemon Jelly Other uses * Sorgenti di Firenze Trekking (SOFT), a system of walking trails in Italy * Soft matter, a subfield of condensed matter * Magnetically soft, material with low coercivity * Soft skills, a person's people, social, and other skills * Soft commodities, or softs *A flaccid penis Tumescence is the quality or state of being tumescent or swollen. Tumescence usually refers to the normal engorgement with blood (vascular congestion) of the erectile tissues, marking sexual excitation, and possible readiness for sexual activity. ..., the opposite of "hard" See also * * * Softener (disambiguation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Flame Structure
A flame structure is a type of soft-sediment deformation that forms in unconsolidated sediments. The weight of an overlying bed forces an underlying bed to push up through the overlying bed, generally when both strata are saturated with water. The resulting pattern (in cross section) may resemble flames. In order for the flame structure to occur, the overlying bed must be of a higher density than the underlying bed, or there must be differential pressures in the upper bed.Anketell, J. M. ''et al.'' (1970) "On the deformational structures in systems with reversed density gradients" ''Rocznik Polskiego Towarzystwa Geologicznego'' (''Annals of the Geological Society of Poland'') 40: pp. 3–30 Basically prior to flaming these structures are unstable, under pressure, and then subject to additional stress, such as being triggered by earthquakes.Brodzikowski, K., and Haluszczak, A. (1987) "Flame structures and associated deformations in Quaternary glaciolacustrine and gla ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Load Casts
Load casts are bulges, lumps, and lobes that can form on the bedding planes that separate the layers of sedimentary rocks. The lumps "hang down" from the upper layer into the lower layer, and typically form with fairly equal spacing. These features form during soft-sediment deformation shortly after sediment burial, before the sediments lithify. They can be created when a denser layer of sediment is deposited on top of a less-dense sediment. This arrangement is gravitationally unstable, which encourages formation of a Rayleigh-Taylor instability if the sediment becomes liquefied (for instance, by an imposed earthquake shock). Once the sediments can flow, the instability creates the "hanging" lobes and knobs of the load casts as plumes of the denser sediment descend into the less-dense layer. Load casts are a common kind of sole marking. Terminology The expression "load cast", sometimes also called a load structure, refers to a load (the denser layer) sinking into its underl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dish Structure
A dish structure is a type of sedimentary structure formed by liquefaction and fluidization of water-charged soft sediment either during or immediately following deposition. Terminology Due to the similarity in its shape to a dish, the structure, sometimes also referred to as dish-and-pillar or dish-and-pipe , was named after the common kitchen item. History Dish structure was described scientifically for the first time by Crook in 1961 who still used the title ''discontinuous curved lamination''. The established term was used for the first time in 1967 by Stauffer and by Wentworth. Comprehensive studies are due to Lowe and LoPiccolo in 1974 and Lowe in 1975. Description The subhorizontal dish structure consists of two parts, the dish itself and the edimentcontained within the dish plus the region stretching up to the bounding surface of the overlying dish(or dishes) above. The bounding surface of the dish can take on variable shapes, from substantially flat to bowl-like ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sole Markings
Sole marks are sedimentary structures found on the bases of certain strata, that indicate small-scale (usually on the order of centimetres) grooves or irregularities. This usually occurs at the interface of two differing lithologies and/or grain sizes. They are commonly preserved as casts of these indents on the bottom of the overlying bed (like flute casts). This is similar to casts and molds in fossil preservation. Occurring as they do only at the bottom of beds, and their distinctive shapes, they can make useful way up structures and paleocurrent indicators. Sole markings are found most commonly in turbidite deposits, but are also often seen in modern river beds and tidal channels. History Sole markings were first recognized in the Devonian rocks of New York State by James Hall in 1843. Originally, the features found on the undersides of beds were called ''hieroglyphs'', ''fucoids'', and ''bio hieroglyphs'', because of their structure and how they were thought to be ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Seismite
{{Earthquakes Seismites are sedimentary beds and structures deformed by seismic shaking. The German paleontologist Adolf Seilacher first used the term in 1969 to describe earthquake-deformed layers. Today, the term is applied to both sedimentary ''layers'' and soft sediment deformation ''structures'' formed by shaking. This subtle change in usage accommodates structures that may not remain within a layer (i.e., clastic dikes or sand volcanos). Caution is urged when applying the term to features observed in the field, as similar-looking features may be products of either seismic or non-seismic perturbation. Several informal classification systems exist to help geologists distinguish seismites from other soft-sediment deformation features, though a formal, standardized system has not been developed. Geologists use seismites, in combination with other evidence, to better understand the earthquake history of an area. If age and distribution of seismically-generated features can be d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sand Volcano
Sand boils or sand volcanoes occur when water under pressure wells up through a bed of sand. The water looks like it is boiling up from the bed of sand, hence the name. Sand volcano A sand volcano or sand blow is a cone of sand formed by the ejection of sand onto a surface from a central point. The sand builds up as a cone with slopes at the sand's angle of repose. A crater is commonly seen at the summit. The cone looks like a small volcanic cone and can range in size from millimetres to metres in diameter. The process is often associated with soil liquefaction and the ejection of fluidized sand that can occur in water-saturated sediments during an earthquake. The New Madrid Seismic Zone exhibited many such features during the 1811–12 New Madrid earthquakes. Adjacent sand blows aligned in a row along a linear fracture within fine-grained surface sediments are just as common, and can still be seen in the New Madrid area. In the past few years, much effort has gone into the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Clastic Dike
A clastic dike is a seam of sedimentary material that fills an open fracture in and cuts across sedimentary rock strata or layering in other rock types. Clastic dikes form rapidly by fluidized injection (mobilization of pressurized pore fluids) or passively by water, wind, and gravity (sediment swept into open cracks). Diagenesis may play a role in the formation of some dikes. Clastic dikes are commonly vertical or near-vertical. Centimeter-scale widths are common, but thicknesses range from millimetres to metres. Length is usually many times width. Clastic dikes are found in sedimentary basin deposits worldwide. Formal geologic reports of clastic dikes began to emerge in the early 19th century.Cross, W., 1894, Intrusive sandstone dikes in granite, GSA Bulletin, 5, p. 225-230 Terms synonymous with clastic dike include: ''clastic intrusion, sandstone dike, fissure fill, soft-sediment deformation, fluid escape structure, seismite, injectite, liquefaction feature, neptunian dike (p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
