scientists believe that earth's early atmosphere changed in composition as a result of what?

Question

If you could just steer me to the right chapter of understanding this a little better. Thanks in advance.

Answer 1

Photosynthesis. It is thought that prehistoric plants\algae allowed for the conversion of CO2 into O2 and changing the atmospheric conditions. Oxygenation of the oceans caused the dissolved iron to precipitate and form the banded iron formations. O2 in the atmosphere allowed for the development of terrestrial animals.

Answer 2

I hope this is right, but I believe it was the warming of the seas causing the release of tremendous amounts of methane gases stored in the frozen bottom muck which caused a greenhouse affect. while it is true that vulcanism produces sulphur dioxide and many other gases,the release of sulphur is carried into the upper atmosphere and once there , gives super cooled water molecules a nuclei to form on and eventually becomes a haze that will not allow the full warming of the earth. and as this grows thicker with passing time will start as rain and then an ice age will occur.

Answer 3

Typically the only way we capture gases from prehistoric environments is in "ice-cores"

Ice core sampling is performed by drilling in large, thick permanent ice sheets, i.e. Antarctica.

When the ice freezes it traps a very small portion of gas in the ice itself. By taking a core sample and dating the ice, you can deduce what the atmosphere was like at that particular time period.

Usually the change in composition in the atmosphere is a result of increase or decrease in volcanic activity. Volcanoes are known to have high concentrations of sulfur, hydrogen monoxide, carbon dioxide, etc.

As far as I know, the only thing that can change the atmospheric composition quickly is large scale volcanic activity or some other catastrophic event.

Answer 4

I vote for the professor Plants came along and made oxygen. . .One of those plant critters was a Crinoid-read somewhere that is really our ancestor. . .