The
Mid-Atlantic Ridge (MAR) is a
mid-ocean ridge, a
divergent tectonic plate or constructive plate boundary located along the floor of the
Atlantic Ocean, and part of the longest mountain range in the world. In the North Atlantic, it separates the
Eurasian and
North American Plates, whereas in the South Atlantic it separates the
African and
South American Plates. The Ridge extends from a junction with the
Gakkel Ridge (Mid-Arctic Ridge) northeast of
Greenland southward to the
Bouvet Triple Junction in the South Atlantic. Although the Mid-Atlantic Ridge is mostly an underwater feature, portions of it have enough elevation to extend above sea level. The section of the ridge that includes the island of
Iceland is also known as the
Reykjanes Ridge. The ridge has an average spreading rate of about 2.5 cm per year.