Chapter 4-3 Metamorphic Rocks

Metamorphic Rocks

rocks formed from the existing bedrock from the action of :

Heat

Chemicals

Pressure

Time

The newly formed metamorphic rock has the same minerals as the parent rock and therefore will have some similar properties.

How Metamorphic Rocks Form

meta- change morph- form

They are formed through changes produced by natural forces. These natural forces are: * Heat * Pressure * Chemicals

Rock Characteristics

1.) Crystal or Grain Size fine grain

2.) Texture- how the rock looks, NOT how it feels Coarse (large grains) Fine (small grains) Glassy (no visible grains) glassy coarse

3.) Color- tells you what minerals are in the rock

   
Metamorphism:
Foliation
Non-foliation

arrangement of minerals in parallel layers
arrangement of minerals not in parallel layers
Metamorphism- How are they formed:

Regional

-occurs when areas of rock are under intense heat & pressure, such as during mountain-building

-hot liquids and gases also react the rock to help change it with the rock to help change it

How much area is affected:

-large areas

Contact

-occurs when hot magma (from under the earth) moves its way into overlying rock

-hot liquids and gases also react with

-depends on temperature of the magma; the hotter it is, the more area it will affect and vice versa