C1 The Earths Atmosphere and Earths materials Flashcards
Today’s atmosphere
78% nitrogen
21% oxygen
1% other gasses
What where the phases of the atmosphere
1 volcanos gave out gasses
2 green plants evolved and O2 levels raised
3 ozone layer and complex animals
How did earths early atmosphere levels change?
The earth cooled , water vapour condensed to make oceans
CO2 absorbed by oceans and used to make shells. Used in photosynthesis
O2 made in photosynthesis
How humans effect earths atmosphere
Burning fossil fuels + CO2
Deforestation +CO2
Farming livestock +methane
How volcanic activity effects earths atmosphere
SO2 when volcanos erupt
CO2 when volcanos erupt
How do we know about earths early atmosphere
Arctic ice cones -each year another layer added trapping air. The deeper the layer the older the air
Types of rocks
Igneous
Metamorphic
Sedimentary
How are sedimentary rocks formed?
Layers of sediment build up in lakes and oceans
Over millions of years layers develop , this pressure pushes out the water
Natural mineral cement is made through the fluid flowing through the pores
Imprints of dead organisms are not destroyed as there is no heat
How are Metamorphic rocks made?
Heat and pressure on other rocks over long periods of time
Mineral structure and texture may change but chemical composition usually stays the same
Small crystals
How are igneous rocks formed?
When molten magma pushes up or through the earths crust and cools and solidifies . Made of various minerals and randomly arranged crystals
Extrusive igneous rocks
Cool quickly outside the earths crust to make small crystals
Eg basalt and rhyolite
Intrusive igneous rocks
Cool slowly underground making big crystals
Eg granite and gabbro
Exposed by erosion
Uses of limestone
Building materials Statues Roads Glass Cement Concrete
Positives of quarrying
Makes houses and roads
Jobs
Neutralises acidic soil
Neutralised sulpher dioxide
Negatives of quarrying
Noise pollution Destroys habitats Transport - pollution Ugly Ruins landscapes
