The UK's Evolving Physical Landscape Flashcards
How are igneous rocks formed
When molten rock (magma) from the mantle cools down and hardens.
Are igneous rocks soft or hard
Hard
Give examples of igneous rock
Granite
How are sedimentary rocks formed
When layers of sediment are compacted together until they become solid rock
What are the two main types of sedimentary rock in the UK
Carboniferous limestone and chalk from tiny shells and skeletons of dead sea creatures.
Clays and shales are made from mud and clay minerals
Give 2 examples of sedimentary rock
Limestone
Sandstone
Chalk
Clay
How are metamorphic rocks formed
When other rocks (igneous, sedimentary or older metamorphic rocks) are changed by heat and pressure. The new rocks become harder and more compact
Are sedimentary rocks hard or soft
Both
Are metamorphic rocks hard or soft
Hard
What is weathering
The breakdown of rock into smaller pieces. It can be mechanical, chemical or biological
What is erosion
The process that wears away rock. During the last glacial period, ice eroded the landscape
What are post-glacial river processes
Melting ice at the end of glacial periods made rivers much bigger than normal with more power to erode the landscape. The ice also left distinctive landforms when it meltedb
What is hydraulic action
Waves crash against the rock and compress the air in the cracks. This puts pressure on the rock. Repeated compression widens the cracks and makes bits of the rock break off
What is abrasion
Eroded particles in the water scrape and rub against the rock, removing small pieces
What is attrition
Eroded particles in the water smash into each other and break into smaller fragments. Their edges also get rounded off when they rub together
What is chemical weathering
The breakdown of rock by changing its chemical composition