Map showing the location of the Aegir Ridge and other major geological features of the northernmost Atlantic
The Aegir Ridge is an extinct mid-ocean ridge in the far-northern Atlantic Ocean. It marks the initial line of break-up of the northern Atlantic, along which seafloor spreading was initiated at the beginning of the Eocene epoch. Towards the end of the Eocene, a new spreading ridge, the Kolbeinsey Ridge propagated northwards from Iceland, splitting the Jan Mayen Microcontinent away from the Greenland Plate. As the Kolbeinsey Ridge formed, so activity on the Aegir Ridge reduced, ceasing completely at the end of the Oligocene epoch when the Kolbeinsey Ridge reached the Jan Mayen Fracture Zone.