The Rock Cycle

Igneous: rocks that crystallize from a melt

Sedimentary: deposition of material from water or air

Metamorphic: recrystallization by heat, pressure, or fluid

Igneous Rocks

Magma = molten liquid + crystals + gas bubbles

Magmas freeze over a range of temperatures, and composition of the melt changes

Rocks melt over a range of temperatures, and composition of the melt changes

Melt ‚ Bulk Rock

How Magma is Made and Evolves

Partial melting and diversification

Add heat

Add water

Reduce pressure

Cooling and crystallization

Assimilation

Intrusive Rocks

Dikes and sills

Plutons

Batholiths

Volcanoes

How volcanoes erupt: the importance of gas (exsolution)

Lava: pahoehoe, a'a, and pillow

Pyroclastic material: explosive eruptions

Fall out

Pyroclastic flows

Lahars

Types of Volcanoes

Shields

Composite volcanoes (a.k.a. stratovolcanoes)

Calderas

Cones

Tectonics and Igneous Rocks

Oceans are floored by basalt (MOR and hotspots)

Decompression melting of the mantle

Continental basalts: rifts and hotspots

Subduction zones: andesites

Subducted slab and water-fluxing

Continents: granites and rhyolites

Melting of continental crust