Mesozoic Plate Tectonics

About 200 million years ago, at the end of the Triassic period, Pangaea began to break apart, leading to the formation of the continents and oceans we see today.

This breakup event occurred even in the supercontinent Pangaea due to the heat trapped beneath Earth's crust, which caused it to crack and split through a process known as continental rifting. During this process, molten rock from the mantle rose to the surface, creating new ocean basins.

As Pangaea fragmented, the vast Panthalassa ocean that surrounded it also split, forming the individual but interconnected oceans that now cover Earth.

Over millions of years, the movement of continents led to collisions with smaller landmasses, resulting in the formation of towering mountain ranges.

For example, the oceanic Farallon Plate subducted under western North America during the late Jurassic and early Cretaceous periods. This subduction generated igneous intrusions and other geological structures. Over time, these intrusions were uplifted and are now exposed in the Sierra Nevada Mountains.