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24 Cards in this Set

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Any fragment ejected during an eruption.
Smallest ejected material that is < .25mm.
Tephra that is larger than dust, and that is < 2mm.
Tephra that varies in size between 2-64mm, and that also means "little stone".
Largest tephra that has angular edges. This large tephra can be thrown at great distances.
volcanic block
Lava that hardens in air as a round ball and that will flatten on impact.
volcanic bomb
Rapidly moving volcanic debris with hot rocks and poisenous gases.
pyroclastic flow
A stream of lava that is usually basaltic.
lava flows
Hardened lava that blocks a vent. It can cause pressure build-up.
lava plug
Tephra that is deposited at a volcano's base or around it's vent.
A mud flow that usually results from snow melting fast during an eruption, mixing with tephra or pyroclastic flow.
An underground channel through which lava flows, leaving tunnels behind, once lava has exited.
lava tube
Flat section of land built up by layers of lava flows, often from fissures.
lava plateau
Where magma rises near the surface causing land to swell, but not to form a volcano.
lava dome
Lava flows resulting in smooth, ropey surfaces.
Lava flow resulting in rough, jagged surfaces.
Compacted dust and ash resulting in a sedimentar rock.
Water increases the chance of rocks melting and high water content=lower melting temperature.
How water affects magama formation.
With LOW pressure, the temperature decreases so these rocks will melt closer the surface.
How pressure affects "wet rocks".
With HIGH pressure, the temperature will increase so these rocks will melt and form deeper in the earth.
How pressure affects "dry" rocks.
How thick something is, depending on temperature and composition.
This lava has low viscosity, with 52% or less of silica due to rocks in upper mantle.
Viscosity of Basaltic Lava.
This lava has high viscosity, with 66% or higher of silica due to the mixing of silica and water-rich continental crust.
Viscosity of Rhyolitic Lava.
This lava has medium viscosity, with 52-66% of silica due to the melting of oceanic crust.
Viscosity of Andesitic Lava.