Igneous Rocks and Intrusive Igneous Activity

A set of vocabulary flashcards based on igneous rocks and their properties.

Magma

Molten rock material below the Earth's surface, parent material of igneous rock.

Lava

Magma that has reached the Earth's surface.

Plutons

Bodies of magma that cool and solidify beneath the Earth's surface.

Felsic

Silica-rich magma with more than 65% silica; includes abundant sodium, potassium, and aluminum.

Mafic

Silica-poor magma with 45-52% silica; abundant in calcium, iron, and magnesium.

Ultramafic

Magma with less than 45% silica content.

Bowen’s Reaction Series

A model that shows the sequence in which minerals crystallize from magma based on their melting points.

Viscosity

Resistance to flow; affected by temperature and composition of magma.

Aphanitic

Fine-grained texture resulting from rapid cooling of lava or magma.

Phaneritic

Coarse-grained texture resulting from slow cooling, where crystals can be identified without a microscope.

Porphyritic Texture

Rock texture characterized by large crystals (phenocrysts) embedded in a finer-grained matrix (groundmass).

Glassy Texture

Texture formed from very rapid cooling, resulting in rocks like obsidian without crystal structure.

Xenoliths

Fragments of rock that become dislodged from surrounding rock and are enclosed within a magmatic body.

Batholiths

The largest type of pluton, covering an area greater than 100 square kilometers.

Partial Melting

The incomplete melting of a rock, where minerals with higher melting points remain solid while others turn to magma.