Science Vocab Chapter 18

Front 1

Batholith

Back 1

Coarse-grained, irregularly shaped, igneous rock mass that covers at least 100 km sq., generally forms 10-30 km below Earth’s surface, and is common in the interior of major mountains chains.

Front 2

Caldera

Back 2

Large crater, up to 50 km in diameter, that can form when the summit or side of a volcano collapses into the magma chamber during or after an eruption.

Front 3

Cinder Cone

Back 3

Steep-sided, generally small volcano that is built by the accumulation of tephra around the vent.

Front 4

Composite Volcano

Back 4

Generally cone-shaped with cancave slopes; built by violent eruptions of volcanic fragments and lava that accumulate in alternating layers.

Front 5

Conduit

Back 5

A tubelike structure that allows lava to reach the surface.

Front 6

Crater

Back 6

Bowl-shaped depression that forms around the central vent at the summit of a volcano.

Front 7

Dike

Back 7

Pluton that cuts across preexisting rocks and often forms when magma invades cracks in surrounding rock bodies.

Front 8

Fissure

Back 8

Are long cracks in the Earth.

Front 9

Flood Basalt

Back 9

Huge amounts of lava that erupt from fissures.

Front 10

Hot Spot

Back 10

Unusually hot area in Earth’s mantle where high-temperature plumes of mantle material rise toward the surface.

Front 11

Laccolith

Back 11

Relatively small, mushroom-shaped pluton that forms when magma intrudes into parallel rock layers close to Earth’s surface

Front 12

Pluton

Back 12

Intrusive igneous rock body, 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.

Front 13

Pyroclastic Flow

Back 13

Swift-moving, potentially deadly clouds of gas, ash, and other volcanic material produced by a violent eruption.

Front 14

Shield Volcano

Back 14

Broad volcano with gently sloping sides built by nonexplosive eruptions of basaltic lava that accumulates in layers.

Front 15

Sill

Back 15

Pluton that forms when magma intrudes parallel rock layers.

Front 16

Stock

Back 16

Irregularly shaped pluton that is similar to a batholith but smaller, generally forms 5-30 km beneath Earth’s surface, and cuts across older rocks.

Front 17

Tephra

Back 17

Rock fragments, classified by size, that are thrown into the air during a volcanic eruption and fall to the ground.

Front 18

Vent

Back 18

Opening in Earth’s crust through which lava erupts and flows out onto the surface.

Front 19

Viscosity

Back 19

A substance’s internal resistance to flow.

Front 20

Volcanism

Back 20

Describes all the processes associated with the discharge of magma, hot water, and steam.