The Middle Jurassic is the second geological epoch in the Jurassic. It began 174.1 million years ago, and ended at 163.5 million years ago.
In the Middle Jurassic, Pangaea began to split apart. It began to separate into Laurasia and Gondwana, and the Atlantic Ocean formed. Tectonic activities closed the Paleo-Tethys Ocean.[1] A subduction zone[2] on the coast of western North America continues to create the ancestral Rocky Mountains.