What is the Mid-Atlantic Ridge?
Quick answer
The Mid-Atlantic Ridge is a huge underwater mountain range running down the middle of the Atlantic Ocean, about 16,000 km (10,000 mi) long, from near the Arctic to near Antarctica. It marks where tectonic plates are pulling apart, creating new seafloor. It rises above sea level in a few places, most famously Iceland.
Key facts
- Length
- About 16,000 km (10,000 mi)
- Spreading rate
- About 2–5 cm a year
- Above sea level
- Iceland, the Azores and other islands
- Part of
- The global mid-ocean ridge system
Plates pulling apart
| Plate boundary | Sides |
|---|---|
| North Atlantic | North American Plate and Eurasian Plate |
| South Atlantic | South American Plate and African Plate |
Molten rock rises into the gap and cools to form new ocean floor, a process called seafloor spreading. The Atlantic widens by a few centimeters a year, about as fast as fingernails grow. That’s why the Atlantic is growing while the Pacific shrinks; see the largest ocean.
Who discovered it?
| Year | Discovery |
|---|---|
| 1870s | The British ship HMS Challenger found signs of a rise in the middle of the Atlantic |
| 1920s | German ships used echo sounding to map it further |
| 1950s | Marie Tharp and Bruce Heezen created detailed maps and found a rift valley running down its center |
Tharp’s maps were key evidence for plate tectonics, confirming Alfred Wegener’s earlier idea of continental drift; see what Pangaea was.
Iceland: the ridge above water
In Iceland, you can see the ridge on land. At Þingvellir National Park, a rift valley separates the plates, and divers swim between continents in the clear Silfra fissure. The ridge’s volcanic heat powers Iceland’s geothermal energy; see where the Blue Lagoon is.
Life on the ridge
Along the ridge are hydrothermal vents, such as the Lost City field, where hot, mineral-rich water rises from the seafloor. They support unusual life that doesn’t depend on sunlight; see the ocean’s twilight zone for life in dark waters.
Part of a bigger system
The Mid-Atlantic Ridge is part of the mid-ocean ridge, the longest mountain range on Earth, about 65,000 km in total; see the longest mountain range.
Still curious?
Jump to a random question from the archive.