Igneous Rocks

Igneous Rocks

Rocks formed from the solidification of molten material (magma or lava).

Three Types of Igneous Rock

Intrusive, Extrusive, and Plutonic.

Magma vs. Lava

Magma is molten rock beneath the earth's surface, while lava is magma that reaches the surface.

Extrusive Igneous Rocks

Rocks formed from lava that cools quickly on the Earth's surface.

Intrusive Igneous Rocks

Rocks formed from magma that cools slowly beneath the Earth's surface.

Crystal Size and Cooling Rate

Faster cooling results in smaller crystals; slower cooling leads to larger crystals.

Bowen's Reaction Series

A sequence that illustrates the crystallization of minerals from cooling magma.

Magma Viscosity Influencers

Silica content, amount of dissolved volatiles, and temperature affect viscosity.

Mafic

Igneous rocks with low silica content and high iron/magnesium, typically dark in color.

Felsic

Igneous rocks with high silica content and low iron/magnesium, typically light in color.

Chemical Composition Evolution

Processes like fractional crystallization and magma mixing affect composition.

Composition Evolution Case

Typically, magma becomes more felsic over time due to the removal of mafic minerals.

Magma Production Mechanisms

Processes such as decompression melting, flux melting, and heat transfer melting produce magma.

Volcano

An opening in the Earth's crust through which lava, gases, and ash erupt.

Grain Size/Texture Terms

Aphanitic (fine-grained), Phaneritic (coarse-grained), Porphyritic (mixed grain size).

Granite

A felsic, phaneritic igneous rock, typically light-colored.

Basalt

An ultramafic, aphanitic igneous rock, commonly found in oceanic crust.

Partial Melting

A process where only a portion of a solid is melted, affecting the resulting magma's composition.