What is the Mid-Atlantic Ridge?
The Mid-Atlantic Ridge is a huge underwater mountain range that runs from just 333 km (207 mi) south of the North Pole to Bouvet Island, located in the Atlantic ocean at a longitude just below South Africa. The Mid-Atlantic Ridge, about 10,000 km (6,200 mi) long, connects to a series of oceanic ridges that encircle the entire planet, with a total length of about 40,000 km (25,000 mi). The Mid-Atlantic Ridge is caused by seafloor spreading, the volcanic activity that happens in the central areas of oceanic crust to replenish crust lost through subduction (sliding) under contintental plates. As the subduction only occurs at a rate of 2.5 cm (1 in) a year, only modest volcanic activity is necessary to replenish the lost crust, though over geological time it can create great mountain ranges.
Although the existence of the Mid-Atlantic Ridge was first inferred by Matthew Fontaine Maury in 1850, it was not discovered until 1872, when an expedition of the HMS Challenger discovered the ridge while scouting for a transatlantic telegraph cable. In 1925, a confirmation of the ridge, as well as additional details, were uncovered by sonar. It was found to be 300 to 600 miles wide, consisting of a parallel series of ridges increasing in height. The Mid-Atlantic Ridge is about two miles (3.2 km) above the sea floor, which has an average depth of three miles (4.8 km). The Mid-Atlantic Ridge serves to divide the Atlantic sea floor into two distinct basins.
Some peaks of the Mid-Atlantic Ridge are so tall that they rise above the waterline to form islands. These include Jan Mayen in the Arctic Ocean, Iceland, the Azores, Bermuda (which initially formed on the ridge but is now far west), the Saint Peter and Saint Paul Islets, Ascension Island, Tristan da Cunha (which has the highest point on the Mid-Atlantic Ridge, Queen Mary's Peak, 2 km above sea level), Gough Island, and Bouvet Island. Many of these islands are inhabited. The Mid-Atlantic Ridge is not a continuous line, but rather consists of many sections misaligned with the others, due to millions of years of intense geological activity.
Written by Michael Anissimov
