Metamorphic Rocks

Metamorphic rocks form due to increased heat, increased pressure, and hydrothermal solutions– Heat – comes from 2 sources: magma and depth– Pressure – increased depth – Hydrothermal solutions – promotes re-crystallization

Types of Metamorphism• Contact Metamorphism – exposure to hot magma

can cause low-grade metamorphism– Ex: magma flows into limestone rock and turns it into marble

• Regional Metamorphism – large areas of rock exposed to extreme heat and pressure– Ex: mountain building/convergent boundaries

Classifying Metamorphic Rocks

• The first type of metamorphic rocks are foliated• Foliated is when the mineral grains in the rock

have been squeezed and flattened into a sheet-like appearance

• Other types of foliated metamorphic rocks may look like sheets of rocks stacked on top of one another

The metamorphic rock Slate

• The other type of metamorphic rock is nonfoliated

• Nonfoliated metamorphic rocks have mineral grains that are arranged randomly

Making Metamorphic Rocks

The sedimentary rock Shale can be metamorphosed into the Metamorphic rock Slate

Making Metamorphic Rocks

The igneous rock Granite can be metamorphosed into the Metamorphic rock Gneiss

Making Metamorphic Rocks

The sedimentary rock Limestone can be metamorphosed into the Metamorphic rock Marble