How did tectonic plates affect the early atmosphere?
Tectonic plate movements caused tectonic activites like converging of plates which resulted in forming of volcanoes.
In plate tectonics there is three plate movements, converging, diverging and transform plate boundaries. Now for converging plate boundaries, there would most of the time be volcanoes formed. If you search on the internet, volcanoes usually emit gases like water vapour, carbon dioxide, sulfur dioxide and carbon monoxide. If you had realised, these are greenhouse gases and as greenhouse gases, they would trap heat from the sun and therefore causing the heating of the earth's atmosphere.