Igneous Rocks and Processes

These flashcards cover essential vocabulary and key concepts related to the formation, classification, and characteristics of igneous rocks.

Magma

Molten rock that cools and solidifies to form igneous rocks.

Lava

Magma that reaches the Earth's surface.

Crystallization

The cooling of magma resulting in the orderly arrangement of ions into crystals.

Silicon-oxygen tetrahedron

The basic building block of silicate minerals formed by the linkage of silicon and oxygen atoms.

Plutonic rocks

Igneous rocks that crystallize at depth, characterized by a coarse-grained texture.

Extrusive igneous rocks

Rocks formed from the solidification of lava or volcanic debris at the surface.

Granitic composition

Light-colored igneous rocks composed almost entirely of quartz and potassium feldspar.

Basaltic composition

Dark igneous rocks that contain a higher density of dark silicates and calcium-rich feldspar.

Andesitic composition

Intermediate igneous rocks that contain at least 25% dark silicate minerals.

Ultramafic composition

Igneous rocks mostly made up of olivine and pyroxene, primarily from the upper mantle.

Aphanitic texture

Fine-grained texture resulting from rapid cooling of magma.

Phaneritic texture

Coarse-grained texture resulting from slow cooling of magma.

Porphyritic texture

A texture in igneous rocks where large crystals (phenocrysts) are embedded in a finer-grained matrix.

Glassy texture

A texture formed from very rapid cooling, causing ions to freeze in place without forming crystals.

Decompression melting

Melting that occurs due to a reduction in pressure, allowing solid hot mantle rocks to ascend and melt.

Bowen's reaction series

The systematic order of crystallization of minerals based on their melting points as magma cools.

Partial melting

Process where certain minerals melt while others remain solid, altering the composition of magma.

Assimilation

The process by which magma incorporates surrounding rock as it migrates through the crust.

Magma mixing

The process in which two chemically different magma bodies merge during their ascent.