Chapter 6: Up from the Inferno - Magma and Igneous Rocks

These flashcards cover essential vocabulary terms related to magma, igneous rocks, and their characteristics as discussed in the provided chapter notes.

Rock

A coherent, naturally occurring solid that consists of an aggregate of minerals or, less commonly, a body of glass.

Clastic Rock

Rocks held together by cement, formed by the accumulation of sediment.

Crystalline Rock

Rocks held together by interlocking crystals, typically formed from molten material.

Bedrock

A coherent mass of rock attached to Earth’s crust; not broken pieces of rock.

Igneous Rock

Rock formed from molten material, categorized into intrusive and extrusive types.

Metamorphic Rock

Rock formed when pre-existing rocks change character due to temperature and/or pressure conditions.

Sedimentary Rock

Rock formed by cementation or precipitation of sediments.

Viscosity

Resistance to flow; it affects the speed at which molten rock moves.

Decompression Melting

Melting that occurs when pressure decreases but temperature remains constant, creating a liquid.

Flux Melting

Melting that occurs with the help of volatiles breaking chemical bonds, typically at subduction zones.

Bowen's Reaction Series

A sequence that illustrates the order in which minerals crystallize from cooling magma.

Pyroclastic Flow

Deadly, fast-moving avalanches of superheated volcanic ash and debris.

Dike

A vertical intrusion that cuts across rock layers.

Sill

A horizontal intrusion that runs parallel to rock layers.

Laccolith

A blister-shaped intrusive body of magma that accumulates underground.

Pluton

Blob-shaped intrusions that solidify from magma chambers.

Batholith

A group of plutons covering a large area, typically formed at convergent plate boundaries.

Xenolith

Chunks of wall rock incorporated into magma without fully melting.

Fragmental Texture

Igneous rocks composed of welded together chunks and shards.

Glassy Texture

Solid glass or glass shards with no visible crystals.

Aphanitic Texture

Fine-grained texture in which mineral grains are too small to be seen without a microscope.

Phaneritic Texture

Coarse-grained texture in which mineral grains are visible to the naked eye.