The Paleozoic era is followed by the Mesozoic era. The Mesozoic era consists of three periods Triassic, Jurassic, and Cretaceous.
During the cretaceous period the temperature of earth was 10 to 15 °C warmer than it is today. This warmth was caused due to the increase in volcanic activity of Earth. As the tectonic plates were moving this created mantle from the Earth's core rose to the surface causing increased volcanic activity. This volcanic activity increased the amount of CO₂ in the atmosphere thus creating the greenhouse effect.
The Paleozoic era spanned from the Cambrian to the Permian and ended with a mass extinction at the end of the Permian. Geologists are still unsure of the cause but the theories include a meteorite impact or a massive volcanic event in Siberia or a combination of both. This could be a possible cause of the melting of the late Paleozoic ice sheets.
Any student who states that tectonic plates are too massive to move doesn't understand how much heat exists in the center of the earth. This heat is capable of moving the most massive of plates.
