Unit 4 - Earth Flashcards
(12 cards)
Who created the theory of the continental drift ?
Alfred Wegeber - 1912
Pangea -
Current separated continents were once all connected in one single supercontinent
How did Pangea seperate?
Move due to tectonic plates
How did the tectonic plates move?
Convention currents in the molten rock in the mantle below the crust.
What can occur from economic plates moving?
Volcanos
Earthquakes
Constructive plate boundary
Plates move apart
Magma from below surface is released
Can cool to form igneous rock
Volcanoes are formed as magma wells up to fill gap
Eventually new crust formed
Occurs at mid ocean ridge - new island can form - how Iceland was formed
Destructive plate boundary
Oceanic and continental plates move towards eachother
Oceanic plate dense - forces under the lighter continental plate - process is subduction
Friction causes melting of the oceanic plate - earthquakes could occur
Magma rises up through cracks and erupts onto surface - volcanoes
Conservative plate boundary
Plate slide past eachother at different speeds
Friction is overcome and the plates slip past in sudden movement .
Shockwaves created - earthquake
- example - San Andreas fault
Fossil fuels in environment
Burning fossil fuels (coal) - global warming
Releases sulfur dioxide
Sulfur dioxide forms into sulphuric acid on contact with water
Causes acid rain
Acid rain lowers PH of water
Causes damage to aquatic life
Damages forests, vegetation
Corrosion of metal structures
Buildings made of limestone can have damage from acid rain.
Atmosphere creation
1) volcanoes released co2, methane, ammonia and water vapour
2)earth temp decrease - vapour condensed and collected to form oceans.
3)plants first type of life. Photosynthesis introducing oxygen to atmosphere.
4) methane level decrease - reacted with oxygen to give co2 and water. Nitrogen level increased due to this.
5) co2 levels decreased by photosynthesis,locked in fossil fuels and dissolved in oceans to form carbonate rocks and sediments.
Plate tectonics
Crust and upper part of mantle are fragmented into tectonic plates.
Plates float on mantle
Convention currents - drift
Plates move suddenly - earthquake
earths outer layer - lithosphere ,broken into 7-8 major and many minor plates.
Process which contribute to composition of atmosphere and its effect
Combustion - combustion of a fuel creates ENERGY+CO2+H2O - co2 contributes to global warming
Respiration - chemical reaction, happens in all living cells - energy released from glucose for our cells to keep us functioning.
Photosynthesis - green plants absorb light energy using chlorophyll. CO2 + H2O = glucose
- glucose used in respiration and O2 produced
