Magma and metamorphism

Magma

extremely hot liquid and semi-liquid rock located under Earth’s surface.

Lava

when magma flows or erupts onto Earth’s surface,

1. water vapor

2. carbon dioxide

3. sulfur

magma also contains small amounts of dissolved gases such as…

high temperatures and pressure under Earth’s crust

what keeps magma in its fluid state

1. basaltic

2. andesitic

3. rhyolitic

three basic types of magma:

silicon dioxide

All types of magma have a significant percentage of…

Basaltic magma

high in iron, magnesium, and calcium but low in potassium and sodium. It ranges in temperature from about 1000oC to 1200oC (1832oF to 2192oF).

Andesitic magma

has moderate amounts of these minerals, with a temperature range from about 800oC to 1000oC (1472oF to 1832oF).

Rhyolitic magma

high in potassium and sodium but low in iron, magnesium, and calcium. It occurs in the temperature range of about 650oC to 800oC (1202oF to 1472oF).

metamorphism

changes in mineral assemblage and texture that result from subjecting a rock to conditions such pressures, temperatures, and chemical environments different from those under which the rock originally formed.

Contact metamorphism

occurs adjacent to igneous intrusions and results from high temperatures associated with the igneous intrusion.

contact aureole

only a small area surrounding the intrusion is heated by the magma, metamorphism is restricted to the zone surrounding the intrusion, called

Regional Metamorphism

occurs over large areas and generally does not show any relationship to igneous bodies. Most are accompanied by deformation under non-hydrostatic or differential stress conditions.

Cataclastic metamorphism

occurs as a result of mechanical deformation, like when two bodies of rock slide past one another along a fault zone.

Hydrothermal Metamorphism

Rocks that are altered at high temperatures and moderate pressures by hydrothermal fluids are hydrothermally metamorphosed.

Burial Metamorphism

When sedimentary rocks are buried to depths of several kilometers,

Shock Metamorphism (Impact Metamorphism)

When an extraterrestrial body, such as a meteorite or comet impacts the Earth or if there is a very large volcanic explosion,