lesson 20/21: metamorphic rock

Question 1

intro

Answer 1

Rocks do not always need to be buried to great depths to experience metamorphism. This image shows how rocks can be changed by the high temperatures that result from contact with hot magma. The metamorphic rocks around the body of magma are baked by the heat escaping the cooling magma body.

Question 2

information

Answer 2

Rocks pushed deep below the Earth’s surface are buried under the weight of the rocks, sediments and soil above them. They are also subjected to higher temperatures with depth. On average, the temperature increases by about 25 °C for every kilometre below the surface. Added heat and pressure can change the type and appearance of the minerals in rocks.

Question 3

the changes that take place during the formation of metamorphic rock depend on:

Answer 3

• the type of original rock, sometimes called the ‘parent’ rock
• the amount of heat to which the original rock is exposed
• the type and amount of pressure added to the rock
• how quickly the changes take place.

Question 4

general info

Answer 4

• Classified of how they are formed
• Igneous rocks come from the formation of magma
• Sedimentary rocks from the compaction and cementation of sediments
• Metamorphic undergo some sort of change
• Metamorphic rocks are changed as a result of exposure to intense heat or/and pressure

Question 5

how many types of metamorphism

Answer 5

2 - contact and regional

Question 6

contact

Answer 6

• Contact metamorphism involves existing rocks coming into contact with really intense heat which is generally provided by lava or magma
• If magma comes through the crust, exposing rocks that will be burnt by the heat of the magma. This causes them to metamorphize into something new

Question 7

regional metamorphism

Answer 7

• Regional metamorphism forms at the fault between to converging plate boundaries
• The rocks that are trapped in between these two tectonic plates are exposed to huge amounts of pressure causing them to metamorphosize
• If you take a rock such as shale and add heat and pressure it would turn into slate. If this is continued , eventually you would reach gneiss. If any more pressure/heat is added to gneiss it would turn into magma and then back to an igneous rock

Question 8

foliation

Answer 8

refers to the layering of minerals in a rock, which gives the rock a layered appearance

Question 9

foliated

Answer 9

Composed of or separable into layers