Volcanoes and Igneous Rocks Vocabulary

Flashcards covering key vocabulary related to volcanic eruptions and igneous activity.

Magma

Molten rock beneath Earth’s surface.

Liquidus

When solidfication begins.

Solidius

Temperature when solidfication is complete.

Volatiles

Compounds that evaporate easily (H2O, CO2).

Felsic Magma

Magma with high silica content.

Mafic Magma

Magma with low silica content.

Extrusive Igneous Rock

Rock that solidifies after coming out of a volcano onto the surface.

Intrusive Igneous Rock

Rock that solidifies underneath the volcano

Plutions

Blob-shaped, large body of magma that solidifies under the rock.

Dikes

Wall-shaped intrusion of magma.

Sills

Magma squeezed between existing rock layers.

Viscosity

Measure of a substance's resistance to flow.

Pahoehoe

Slow-moving, low-volume mafic lava flow.

A'a

Fast-moving, large-volume mafic lava flow.

Plinian Eruptions

Vertical eruption with large quantities of pumice, ash, and pyroclastic flows.

Pyroclastic Flows

Super fast flows of hot gas and volcanic matter, almost impossible to avoid.

Phreatic & Phreatomagmatic Eruption

Eruption caused by water introduced to magma.

Lahars

Muddly slurries of ash, melted snow, and rain.