The Gakkel Ridge is a mid-oceanic ridge located in the Arctic Ocean between Greenland and Siberia with a length of about 1800 kilometers.
The Gakkel Ridge is the slowest spreading ridge on earth. Until 1999, when scientists, operating from a nuclear submarine, discovered active volcanos along this ridge, the Gakkel Ridge was believed to be non-volcanic. In 2001 two research icebreakers, the German Polarstern and the US Healy, with several groups of scientists were sent to the Gakkel Ridge to explore the ridge and to collect petrological samples. Among other discoveries, many hydrothermal vents ("black smokers") were surprisingly discovered during this expedition. This finding is difficult to explain with current models for sea floor spreading.