Precambrian
The Precambrian is divided into the Hadean, Archaean and Proterozoic eons. The Precambrian eon spans from the formation of Earth around 4500 Ma (million years ago) to c. 542 Ma.
The area we now call the North Sea was interspersed amid several separate continental areas (Siberia, Baltica, Gondwana, and Laurentia) as well as the Iapetus Ocean and Tornquist Sea. Plate tectonics and continental collisions (orogenies) brought the features together of the North Sea that we recognise presently.
Read more about this topic: Geology Of The North Sea