Types of Rock
3 types of rock: igneous, metamorpic+sedimentary
Igneous rock formed from magma that's cooled down
Sedimentary rock formed from a compacted sediment
Metamorphic rock formed by heat and pressure.
The Rock Cycle
The formation of all rock types is linked by the rock cycle:
1) Weathering creates loose sediment
2) Easier for erosion to occur
3) Sediment is transported away and deposited on the sea bed
4) Sediment is compacted on the sea bed through lithification to form sedimentary rocks
5) Heat and pressure can change any rock type to new metamorphic rock
6)Melting of any rock type creates magma. When magma cools down-igneous rocks formed
Gological time is on a much Larger scale than Human Time.
3 types of weathering: Mechanical, Chemical and biological
Mechanical Weathering-rocks are broken down by physical processes:
2) Exfoliation weathering
Chemical Weathering- rocks are broken down by being dissolved:
1) Solution weathering
2) Carbonation weathering
Biological Weathering-rocks are broken down by plants and animals.
Rocks and landscapes
The type of rock in an area affects the type of landscape that forms.
Granite Landscapes have tors and Moorland:
1) Granite has lots of joints which aren't evenly spread
2) Freeze-thaw and chemical weathering wear down the parts of the rock with lots of joints faster because there are more cracks for water to get into.
3) Fewer joints in granite-slower the weathering is
4) Granite is impermeable-doesn't get water through
5) Creates moorlands-large areas of waterlogged and acidic soil
Chalk and Clay landscapes have escarpments and vales