What's So Exciting About Midocean Ridges?

Fire + Ice: Exploring for Volcanoes Beneath the Arctic
The Arctic Mid-Ocean Ridge Expedition
July 31 - October 3, 2001

The mid-ocean ridge system forms the longest continuous, volcanic mountain range on Earth. Even the combined length of the Andes, the Rockies, and the Himalayas is small compared with the length of the mid-ocean ridge system. This amazing, underwater mountain chain stretches for over 70,000 km —more than 43,000 miles! It is the most active volcanic mountain chain on the Earth, generating about 20 cubic kilometers of magma each year.

In the context of plate tectonics, the critical process that has shaped the Earth and its continents, a mid-ocean ridge represents a boundary between two lithospheric plates. These plates are moving away from each other, or spreading apart. As hot mantle material from deep within the Earth rises, it melts, and the magma erupts at the mid-ocean ridges, where new seafloor, or oceanic crust, is created. This is called seafloor spreading.

South America and Africa, for example, were once connected to each other, but that was over 250 million years ago! Since then, seafloor spreading along the Mid-Atlantic Ridge (MAR) pushed the two continents apart. In fact, South America and Africa are still moving away from each other. The Atlantic Ocean is getting wider as we speak.

For those who are interested in geology and volcanic rocks, mid-ocean ridges are a paradise. The lava that erupts offer a unique opportunity to understand the inner workings of our planet. But those who are more interested in the animals that live in the ocean should not despair. Whether you're a geologist or an ecologist, the mid-ocean ridge is a fascinating place!

The mid-ocean ridge also supports a host of unique organisms. These creatures live only around hydrothermal vents, hot geysers of the seafloor that are commonly found along the ridge. The vent fauna and their biology are still virtually undiscovered. Who knows what interesting creatures are waiting to be found?