3 Types of Metamorphism Miss Holl Rowland High

3 Types of Metamorphism Miss Holl Rowland High School October 24, 2006

Outline • Regional metamorphism • Contact metamorphism • Hydrothermal metamorphism

Regional Metamorphism Definition • Rocks are metamorphosed over large areas that are the size of many states or even several countries

Regional Metamorphism • Caused by tectonic plates smashing into each other!

Regional Metamorphism Conditions • High pressure • High temperature Plate tectonics • Continents collide (smash into each other) • Ocean crust subducts

Regional Metamorphism • Pictures

Regional Metamorphism • Himalayan Mountains Continent Collision!

Contact Metamorphism Definition • Hot magma or lava changes (metamorphoses) rocks • Can happen deep underground or at the surface

Contact Metamorphism Conditions • low to moderate pressure (P) – Pressures are generally less than 4 kilobars (Kb) • low to high temperature (T) – Temperatures of metamorphism vary widely from 400 -1000 Celcius (C)

Contact Metamorphism • Pictures

Contact Metamorphism • Pictures

Hydrothermal metamorphism

Hydrothermal Metamorphism Definition • Super-heated ocean water changes rocks • Minerals are dissolved or • mix with ocean water minerals to form new minerals

Hydrothermal metamorphism Conditions • Super-heated ocean water emitted from hydrothermal vents on the ocean floor • High heat • No pressure

Hydrothermal metamorphism • Pictures

Hydrothermal metamorphism • Pictures

Summary Different conditions create different types of metamorphic rocks • High temp, high Pressure - regional metamorphism • High temp, low pressure - contact metamorphism • Hot water - hydrothermal metamorphism