Pyroclastic rock
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Pyroclastic rocks are clastic rocks composed of rock fragments produced and ejected by explosive volcanic eruptions. The individual rock fragments are known as pyroclasts. Pyroclastic rocks are a type
Rocks from the Bishop Tuff, uncompressed with pumice on left; compressed with fiamme on right.
Tephra
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Tephra is fragmental material produced by a volcanic eruption regardless of composition, fragment size, or emplacement mechanism.
Pyroclastic rock
…from the Ancient Greek words pyr, meaning "fire", and klastos, meaning "broken in pieces". Unconsolidated accumulations of pyroclasts are described as tephra. Tephra may become lithified to a pyroclastic rock by cementation or chemical reactions as the result of the passage of hot gases (fumarolic alteration…
Volcanic tephra at Brown Bluff, Antarctica (2016)
Tephra horizons in south-central Iceland: The thick and light-coloured layer at the centre of the photo is rhyolitic tephra from Hekla.
Molten lava fountain at Kilauea volcano on Hawaii, with black cloud of associated tephra