Mesozoic the Innuitian orogeny, the Brooks Range, the Verkhoyansk and Cherskiy Ranges in Siberia, and the Khingan Mountains in Manchuria. This orogeny was related to the opening of the Arctic Ocean and subduction of the North China and Siberian cratons under the Pacific Ocean. In contrast, the era featured the dramatic rifting of the supercontinent Pangaea, which gradually split into a northern continent, Laurasia, and a southern continent, Gondwana. This created the passive continental margin that characterizes most of the Atlantic coastline (such as along the U.S. East Coast) today. By the end of the era, the continents had rifted into
Geology of the North Sea zone. The Triassic saw active crustal stretching via the rifting process, lower sea levels and volcanic activity. As the Jurassic (200–145 Ma) started, Pangaea began to break up into two continents, Gondwana and Laurasia. At this time sea levels rose. The burial of algae and bacteria below the mud of the sea floor during this time resulted in the formation of North Sea oil and natural gas, much of it trapped in overlying sandstone by deposits formed as the seas fell to form the swamps and salty lakes and lagoons that were home to dinosaurs. Volcanism and a rift system