Igneous Rocks and Volcanoes

Flashcards covering key vocabulary and definitions related to igneous rocks and volcanic activity.

Ignous Rocks

Rocks formed through the cooling and crystallization of molten rock (magma/lava).

Magma

Molten or partially molten material found beneath Earth’s surface.

Lava

Molten rock that reaches the surface.

Extrusive Rocks

Igneous rocks that form from lava cooling on the surface of Earth (volcanic).

Intrusive Rocks

Igneous rocks that form from magma cooling beneath Earth’s surface (plutonic).

Felsic

Igneous rocks that are high in minerals with silica and low in iron and magnesium.

Mafic

Igneous rocks that are low in minerals with silica and high in iron and magnesium.

Ultramafic

Igneous rocks that are very low in minerals with silica and very high in iron and magnesium.

Pyroclastic Material

Particles violently blown out of the volcano that reach the ground, classified based on size.

Volcano

Structure formed when magma becomes lava and erupts onto the surface.

Lahar

Fast-moving volcanic mud flow from the mixing of water and ash.

Caldera

A gigantic volcanic depression, much larger than a crater, formed when a magma chamber empties and the volcano collapses.

Strombolian Eruptions

Regular eruptions of magma characterized by 'burps' approximately every 10 to 20 minutes.

Vulcanian Eruptions

Moderately sized explosive eruptions that emit pyroclastic material.

Plinian Eruptions

Huge explosive eruptions that eject large quantities of material, often destroying parts of the volcano.

Gas Composition

Magma composition controls gas content, affecting eruption style.

Volcanic Gas

Gas expelled as magma rises, including water vapor, carbon dioxide, and sulfur dioxide.

Vesicles

Tubular holes preserved in volcanic rock caused by the escape of gases from lava.

Pahoehoe Lava

Mafic lava that has a glassy, ropy texture formed from surface cooling.

Aa Lava

Igneous lava with a jagged, blocky texture formed from continuing flow underneath the surface.

Composite Volcano

A volcano made of alternating layers of lava, pyroclastic material, and debris, often explosive.

Shield Volcano

A type of volcano with gentle slopes formed by low viscosity, non-explosive lava flows.

Cinder Cone

A steep-sided volcano built from the accumulation of pyroclastic material, often explosive.

Eruptive Style

The pattern and characteristics of how a volcano erupts, including effusive and explosive styles.

Supervolcano

A type of volcano characterized by a massive explosion, producing a caldera much larger than typical volcanoes.