15 terms

Glencoe Science Earth Science Chapter 18 Volcanic Activity

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viscosity
a substance's internal resistance to flow
pluton
intrusive igneous rock bodies, including batholiths, stocks, sills, and dikes, formed through mountain-building processes and oceanic-oceanic collisions; can be exposed at Earth's surface due to uplift and erosion
batholith
coarse-grained, irregularly shaped, igneous rock mass that covers at least 100 km2 (squared), generally forms 20-30 km below Earth's surface, and is common in the interior of major mountain chains
stock*
irregularly shaped pluton that is similar to a batholith but smaller; generally forms 10-30 km beneath Earth's surface, and cuts across older rocks
sill
pluton that forms when magma intrudes parallel rock layers
dike
pluton that cuts across preexisting rocks and often forms when magma invades cracks in surrounding rock bodies
vent
opening in Earth's crust through which lava erupts and flows out onto the surface
crater
bowl-shaped depression, usually less than 1 km in diameter, that forms around the central vent at the summit (top) of a volcano
caldera
large crater, up to 50 km in diameter, that can form when the summit (top) or side of the volcano collapses into the magma chamber during or after an eruption
shield volcano
broad volcano with gently sloping sides built by non explosive eruptions of basaltic lava that accumulates in layers
cinder-cone volcano
steep-sided, generally small volcano that is built by the accumulation of tephra around the vent
composite vocano
large, sloping volcano built by violent eruptions of volcanic fragments and lava that accumulates in alternating layers
tephra
rock fragments, classified by size, that are thrown into the air during a volcanic eruption and fall to the ground
pyroclastic flow
swift-moving, potentially deadly clouds of gas, ash, and other volcanic materials produced by a violent eruption
hot-spot
unusually hot area in Earth's mantle that is stationary for long periods of time, where high-temperature plumes of mantle material rise toward the surface