The longest mountain chain is underwater
The mid-ocean ridge system runs about 65,000 kilometres, longer than the Andes and the Rockies combined, and almost all of it is submerged.
Established2 min read
Sonar surveys after the Second World War, and the maps drawn from them, showed a continuous rise down the Atlantic, through the Indian Ocean, and across the Pacific. New crust forms along the crest and moves away. That is seafloor spreading, the mechanism under plate tectonics.
Iceland is one of the few places the ridge comes up for air. Everywhere else the peaks stand in the dark, a few kilometres below the waves, broken by fracture zones that offset the line.
Caveats
- It is one connected system, not a single unbroken wall of peaks.
- Length figures vary with how the branches are counted. Sixty-five thousand kilometres is the standard order.
Sources
- 1Heezen B. C., Tharp M., Ewing M.. The Floors of the Oceans: I. The North Atlantic. Geological Society of America Special Paper 65, 1959.