accretion

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Related to accretionary: accretionary growth, accretionary prism

accretion

1. Botany the growing together of normally separate plant or animal parts
2. Pathol
a. abnormal union or growing together of parts; adhesion
b. a mass of foreign matter collected in a cavity
3. Law an increase in the share of a beneficiary in an estate, as when a co-beneficiary fails to take his share
4. Astronomy the process in which matter under the influence of gravity is attracted to and increases the mass of a celestial body. The matter usually forms an accretion disc around the accreting object
5. Geology the process in which a continent is enlarged by the tectonic movement and deformation of the earth's crust

accretion

(aggregation) The increase in mass of a body by the addition of smaller bodies that collide and stick to it. The relative velocity of any two colliding bodies must be low enough for them to coalesce on impact rather than fly apart. Once a large enough body forms, its gravitational attraction accelerates the accretion process. Accreting objects in the Universe are numerous and diverse. They include protoplanets, protostars, black holes, and X-ray binaries. The accretion process is thought to occur generally in the form of a disk. Accretion is now assumed to have had an important role in the formation of the planets from swarms of dust grains. In the outer Solar System the grains were like dirty snowflakes and thus accretion was accelerated. See Solar System, origin.

accretion

[ə′krē·shən]
(astronomy)
A process in which a star gathers molecules of interstellar gas to itself by gravitational attraction.
(civil engineering)
Artificial buildup of land due to the construction of a groin, breakwater, dam, or beach fill.
(geology)
Gradual buildup of land on a shore due to wave action, tides, currents, airborne material, or alluvial deposits.
The process whereby stones or other inorganic masses add to their bulk by adding particles to their surfaces. Also known as aggradation.
(meteorology)
The growth of a precipitation particle by the collision of a frozen particle (ice crystal or snowflake) with a supercooled liquid droplet which freezes upon contact.
References in periodicals archive ?
2007) considered them as a basal accretionary complex, similar to the one exposed further south, between 34[degrees] 32' S and 40[degrees] 57' S, along the Chilean coast (Willner et al.
The Apennines subduction is characterised by compressional seismicity east of the chain, in the frontal accretionary prism, and extensional tectonics to the west, associated to the opening of the Tyrrhenian backarc basin and slab rollback (Pondrelli et al.
Detailed microscopic examination of the volcaniclastic (epiclastic) deposits was carried out, discriminating them into accretionary lapilli tuff and finer grained hyaloclastite tuffs.
1-2), while shell layers from organo-phosphatic brachiopods exhibit a concentric accretionary pattern and sometimes a porous or granular texture (Fig.
They suggest that "existing survey information is inadequate to exclude the possibility of earlier Holocene human occupation" and predict that earlier sites may be found on low energy beach deposits and behind accretionary coastal barriers (e.
Basin development in an accretionary, oceanic-floored fore-arc setting: southern coastal Ecuador during Late Cretaceous-Late Eocene time, Am.
Eighteen contributed chapters honoring Windley's influence are arranged in sections on oceanic and island arc systems and continental growth, the tectonics of accretionary orogens and continental growth, growth and stabilization of continental crust (collisions and intraplate processes), Precambrian tectonics and the birth of continents, and active tectonics and geomorphology of continental collision and growth zones.
However, traces of accretionary lobes extending landwards to the south-east are evident along the southern shores of Al Aryam and suggest that the island is a composite of two former islands that probably nucleated on the vestiges of two(?
Structural style, diapirism and accretionary episodes of the Sinu-San Jacinto Terrane, southwestern Caribbean borderland.
Genetically related "Bathymodiolus" populations also occur on the Barbados Accretionary Prism (BAP) and have been referred to as "Bathymodiolus" sp.