The Earths Early Atmosphere

Why is Evidence of the earths early atmosphere limited

Evidence is limited because of the time scale of 4.6 billion years and theories have changed/developed over time

how were gases introduced into the early atmosphere

There was intense volcanic activity that released gases that formed the early atmosphere

How was the atmosphere at the start of this period (refer to Mars and Venus)

At the start of this period, the atmosphere may have been like the atmospheres of Mars and Venus today: mainly CO2 with little or no O2 (g)

How was nitrogen introduced

-Volcanoes also produced nitrogen (N2 ) which gradually built up in the atmosphere

-there may have been small proportions of methane (CH4 ) and ammonia (NH3 )

How did oceans form

Water vapour condensed into oceans

How did CO2 decrease

CO2 dissolved in the water and carbonates were precipitated producing sediments, reducing the amount of CO2 in the atmosphere