1Gases which make up eath (and %)
Nitrogen 78%, Oxygen 21%, Argon 1%, CO2- 0.04%
23 main steps for earth atmosphere
- - volcanoes emitted large amt of gas.
- - earth cooled- oceans formed plants and algae evolved
- Plants algae produce oxygen, forming atmosphere today
3Early earth
surface released releasing. co2 / nitrogen/water vapour/ ammonia/ methane (green house gases)
4oceans were formed by????
water vapour condensing into liquid forming oceans
5what happened to co2 in earth atmosphere
- - dissolved into oceans
- co2 formed carbonate precipates
- formed sediments on sea bed
- cp2 is absorbed by plants - photsynthesis
6how is limestone formed
calcium carbonate deposits from shells/skeletons/ marine organisms
7why is there little evidence of earths early atmosphere
little evidence as it was 4.6 billion years ago
8how is coal, crude oil and gas formed
- plants absorbed co2 - photosynthesis
- when they die they dont decompose properly
- high temp/ pressures form them
9SIX MARKER- how has earths atmosphere changed since earth formed
- volcanoes release large amounts of nitrogen,co2, methane, water vapour
- earth cooled and water vapour condensed to form oceans
- co2 dissolved in oceans to form carbonates
- carbonates produce sedimentary rocks
- algae plants appear- absorb co2 by photosynthesis and realease o2
- carbon locked up in fossil fuels