UK Evolving physical landscape - 4 - Physical processes Flashcards
How are igneous rocks formed?
Igneous rocks are formed by magma from the interior of the earth.
Magma erupts from the volcano, and then cools to form igneous rock
How are sedimentary rocks formed?
Sedimentary rocks are formed from sediments that have settled on the bottom of a lake, sea or ocean which have been compressed over millions of years
How are Metamorphic rocks formed?
Immense amounts of heat and pressure cause the rock to undergo a chemical change into metamporhic rock
2 types of igneous rocks and characteristics
Granite
Basalt
Igneous rocks are:
Impermiable
and resistant to erosion
Types of metamorphic rock and characteristics
An example of metamorphic rock is slate
Metamorphic rock is very resistant to weathering and erosion and is impermeable
2 Types of Sedimentary rock and characteristics
Chalk and clay
Sedimentary rock is permeable and is found in wide, flat plains
What is freeze-thaw weathering?
- Water enters the rock
- Overnight, water freezes and expands, widening the crack
- Ice melts, water goes into the expanded crack
- Process is repeated until Rock splits
What is biological weathering?
Biological weathering is the effect of plants and animals on rock. Roots and animals burrow down, weakening the structure until it splits away.
Explain one type of biological weathering?
- Plant roots get into small cracks in the rock
- As the roots grow, the cracks become larger
- This causes small pieces of rock to split
What is chemical weathering?
Rain and seawater contain weak acids
Over time, these acids dissolve weak rock like limestone or chalk
Explain one type of chemical weathering
acid rain
What is physical weathering?
animals and roots burrowing into rock
