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Результаты поиска термина [pyroclastic]
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pyroclastic | - Pertaining to fragmented (clastic) rock material formed by a volcanic explosion or ejection from a volcanic vent.
- An igneous rock composed of angular rock fragments that originate from a volcanic explosion.
- (adj.) pertaining to clastic rock particles produced by explosive, aerial ejection from a volcanic vent. such materials may accumulate on land or under water. compare - epiclastic, volcaniclastic, clastic. g. smith & hp
- General term for any rock composed of material ejected explosively from
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pyroclastic deposit |
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pyroclastic flow | - Lateral flowage of a turbulent mixture of hot gases (≈400°c) and unsorted pyroclastic material (volcanic fragments, crystals, ash, pumice, and glass shards) that can move at high speed (100 miles an hour or more). also known as a "glowing avalanche" or "nueé ardente."
- A fast density current of pyroclastic material, usually very hot, composed of a mixture of gasses and a variety of pyroclastic particles (ash, pumice, scoria, lava fragments, etc.); produced by the explosive disintegration of viscous lava in a volcanic crater or by the explosive emission of gas-charged ash from a fissure and which tends to follow topographic lows (e.g. valleys) as it moves; used in a more general sense than ash flow. compare -pyroclastic surge, ash flow, nuee ardente, lahar. sw, sn, gg
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pyroclastic surge | A low density, dilute, turbulent pyroclastic flow, usually very hot, composed of a generally unsorted mixture of gases, ash, pumice and dense rock fragments that travels across the ground at high speed and less constrained by topography than a pyroclastic flow; several types of pyroclastic surges can be specified (e.g. base surge, ash-cloud-surge). compare - pyroclastic flow. sw, sn, gg | |
pyroclastics |
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