Chapter 2 - Rocks Flashcards
How are igneous rocks formed?
Igneous rocks are formed as a result of volcanic activity. They form when magma cools and hardens either above or below the earth’s surface.
Give two examples of an igneous rock.
1) Granite
2) Basalt
Describe how basalt forms.
Basalt forms on the surface of the earth. The lava from the volcano cooks very slowly. Basalt has very small crystals that cannot be seen by the naked eye.Basalt is normal grey/black colour. Basalt can be found at the Giant’s Causeway.
How are sedimentary rocks formed?
Sedimentary rocks were formed from the (remains) sediments of dead plants, fish and other rocks. The sediments compile on the beds of seas, rivers, lakes and the surface of the land where the are then compressed and cemented together.
Give 2 examples of sedimentary rocks.
1) Limestone
2) Sandstone
Describe how limestone is formed.
Limestone is formed from the sediments of tiny sea creatures, fish and shells on the sea bed. The sediments build up and compress and cement together. Limestone is usually white/grey in colour. Limestone is permeable and is used to make building. Lonesome can be found at the Burren, Clare.
How are metamorphic rocks formed?
Metamorphic rocks are ones that were once igneous or sedimentary but were changed due to great heat and/or pressure.
Give 2 examples of metamorphic rocks.
1) Marble
2) Quartzite
Describe the formation of marble.
Marble is formed when molten magma forces its way into a body of limestone. This puts the limestone under great heat and pressure, causing it to morph into marble. Marble can be white, red, green or black. Marble is used in fireplaces and ornaments.
Name 3 ways that fossil fuels are extracted from the earth.
1) Drilling (used to get oil or gas from an underground reservoir)
2) Open cast mining (used to get resources that are close to earth’s surface)
3) Shaft mining (used to get resources deep in the earth)
Name the 3 different kinds of rock.
1) Igneous
2) Sedimentary
3) Metamorphic
