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Agglomerate
Agglomerate (from the Latin agglomerare meaning “to form into a ball”) is a coarse accumulation of large blocks of volcanic material that contains at least 75% bombs. Volcanic bombs differ from volcanic blocks in that their shape records fluidal surfaces: they may, for example, have ropy, cauliform, scoriaceous, or folded, chilled margins and spindle, spatter, ribbon, ragged, or amoeboid shapes. Globular masses of lava may have been shot from the crater at a time when partly molten lava was exposed, and was frequently shattered by sudden outbursts of steam. These bombs were viscous at the moment of ejection and by rotation in the air acquired their shape. They are commonly 1 to 2 feet (30 to 60 cm) in diameter, but specimens as large as 12 feet (3.7 m) have been observed. There is less variety in their composition at any one volcanic centre than in the case of the lithic blocks, and their composition indicates the type of magma being erupted.
Agglomerates are typically found near volcanic vents and within volcanic conduits, where they may be associated with pyroclastic or intrusive volcanic breccias. Older (pre-1970) publications, particularly in Scotland, referred to any coarse-grained volcaniclastic rock as ‘agglomerate’, which led to debris flow deposits, talus deposits and other types of breccia being mistaken for vents. Agglomerates are typically poorly sorted, may contain a fine ash or tuff matrix and vary from matrix to clast support. They may be monolithologic or heterolithic, and may contain some blocks of various igneous rocks. There are various differences between agglomerates and ordinary ash beds or tuffs. Agglomerates are coarser and less frequently well-bedded. Agglomerates can be non-welded or welded, such as coarse basaltic ‘spatter’. They typically form proximally during Strombolian eruptions, and are common at strongly peralkaline volcanoes. Some large agglomerate deposits are deposited from pyroclastic density currents during explosive caldera-forming eruptions, such as at Santorini, Taal, and Campi Flegrei. They may be massive to crudely bedded, and can attain great thicknesses.
Crystalline masses of a different kind occur in some numbers in certain agglomerates. They consist of volcanic minerals very much the same as those formed in the lava, but exhibiting certain peculiarities which indicate that they have formed slowly under pressure at considerable depths. They bear a resemblance to plutonic igneous rocks, but are more correctly to be regarded as agglomerations of crystals formed within the liquid lava as it slowly rose towards the surface, and at a subsequent period cast out by violent steam explosions. The sanidinites of the Eifel belong to this group. At Vesuvius, Ascension, St Vincent and many other volcanoes, they form a considerable part of the coarser ash-beds. Their commonest minerals are olivine, anorthite, hornblende, augite, biotite and leucite.
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Aggregate (noun)
A mass, assemblage, or sum of particulars; something consisting of elements but considered as a whole.
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Aggregate (noun)
A mass formed by the union of homogeneous particles; – in distinction from a compound, formed by the union of heterogeneous particles.
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Aggregate (noun)
A set collection of objects.
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Aggregate (noun)
The full chromatic scale of twelve equal tempered pitches.
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Aggregate (noun)
The total score in a set of games between teams or competitors, usually the combination of the home and away scores
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Aggregate (noun)
Crushed stone, crushed slag or water-worn gravel used for surfacing a built-up roof system.
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Aggregate (noun)
Solid particles of low aspect ratio added to a composite material, as distinguished from the matrix and any fibers or reinforcements, especially the gravel and sand added to concrete.
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Aggregate (noun)
Any of the five attributes that constitute the sentient being.
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Aggregate (adjective)
Formed by a collection of particulars into a whole mass or sum; collective; combined; added up.
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Aggregate (adjective)
Consisting or formed of smaller objects or parts.
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Aggregate (adjective)
Formed into clusters or groups of lobules.
“aggregate glands”
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Aggregate (adjective)
Composed of several florets within a common involucre, as in the daisy; or of several carpels formed from one flower, as in the raspberry.
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Aggregate (adjective)
Having the several component parts adherent to each other only to such a degree as to be separable by mechanical means.
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Aggregate (adjective)
United into a common organized mass; said of certain compound animals.
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Aggregate (verb)
To bring together; to collect into a mass or sum.
“The aggregated soil.”
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Aggregate (verb)
To add or unite (e.g. a person), to an association.
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Aggregate (verb)
To amount in the aggregate to.
“There are ten loads, aggregating five hundred bushels.”
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Agglomerate (adjective)
collected into a ball, heap, or mass
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Agglomerate (noun)
A collection or mass.
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Agglomerate (noun)
A mass of angular volcanic fragments united by heat; distinguished from conglomerate.
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Agglomerate (noun)
An ice cover of floe formed by the freezing together of various forms of ice.
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Agglomerate (verb)
To wind or collect into a ball; hence, to gather into a mass or anything like a mass.
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Aggregate (noun)
a whole formed by combining several separate elements
“the council was an aggregate of three regional assemblies”
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Aggregate (noun)
the total score of a player or team in a fixture comprising more than one game or round
“the result put the sides level on aggregate”
“he set the pace with a one-over-par aggregate of 151”
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Aggregate (noun)
a material or structure formed from a mass of fragments or particles loosely compacted together
“the specimen is an aggregate of rock and mineral fragments”
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Aggregate (noun)
pieces of broken or crushed stone or gravel used to make concrete and in building
“use aggregate for the first layer when filling the trench”
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Aggregate (adjective)
formed or calculated by the combination of several separate elements; total
“the aggregate amount of grants made”
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Aggregate (adjective)
(of a group of species) comprising several very similar species formerly regarded as a single species.
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Aggregate (adjective)
denoting the total supply or demand for goods and services in an economy at a particular time.
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Aggregate (verb)
form or group into a class or cluster
“socio-occupational groups aggregate men sharing similar kinds of occupation”
“the butterflies aggregate in dense groups”
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Aggregate (verb)
collect (related items of content) so as to display or link to them
“tools that aggregate data from all of the security devices are a good first step”
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Agglomerate (verb)
collect or form into a mass or group
“he is seeking to agglomerate the functions of the Home Office”
“these small particles soon agglomerate together”
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Agglomerate (noun)
a mass or collection of things
“a multimedia agglomerate”
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Agglomerate (noun)
a volcanic rock consisting of large fragments bonded together.
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Agglomerate (adjective)
collected or formed into a mass.
Agglomerate Illustrations
