Chapter 4: Igneous Rocks

Rock Cycle

Rocks are classified into three main types - Igneous, Sedimentary, and Metamorphic - based on their formation processes.

Igneous Rock

Formed when hot, molten rock crystallizes and solidifies either below (intrusive) or above (extrusive) the Earth's surface.

Sedimentary Rock

Formed from the accumulation and cementation of sediments derived from pre-existing rocks.

Metamorphic Rock

Forms due to changes in heat, pressure, or mineral-rich fluids altering pre-existing rocks.

Cement

Acts like glue, filling pore spaces between crystals to hold clastic sedimentary rocks together.

Crystals

Interlocking crystals hold crystalline rocks together, indicating igneous or metamorphic origins.

Bedrock

The solid rock underlying soils and other unconsolidated material on Earth's surface, often exposed in outcrops.

Granite

A common crystalline bedrock of the continental crust, typically associated with felsic magmas.

Bowen's Reaction Series

Describes the order of crystallization of minerals from a cooling magma, from mafic to felsic compositions.

Viscosity

A measure of a melt's resistance to flow, influenced by temperature, volatile content, and silica content.

Magma Bodies

Intrusive bodies like sills, dikes, plutons, and xenoliths, and extrusive features like pyroclastic flows and large igneous provinces.

Texture

Describes the appearance of igneous rocks based on crystal size and arrangement, revealing information about their cooling history.