The Mid-Atlantic Ridge is the term used to identify a segment of a massive worldwide mountain range that passes through the center of the earth’s oceans like the seams on a baseball. These mid-ocean ridges mark the line of demarcation between the various tectonic plates that comprise the surface of the earth. In the case of the Mid-Atlantic ridge, the plates in question include the Eurasian plate and the African plate to one side (north to south) and the North American plate and South American plate on the other (again north to south). The Mid-Atlantic Ridge, as the name implies, runs through the relative center of the Atlantic Ocean. Beginning at the island of Iceland, the ridge makes a jagged geologic line through the Atlantic Ocean south until it rounds the south end of Africa. “The highest peaks of the Mid-Atlantic Ridge average more than 3000 m (9800 ft) above the ocean floor and, in some cases, exceed 4000 m (13,000 ft)” (Weihaupt, 1979: 78). Beginning with Plato and the legend of Atlantis to the relatively recent discovery of the black smokers and the fascinating creatures that live there, the Mid-Atlantic Ridge has been an object of interest and conjecture throughout the known history of man.
The first person to suggest the idea of a Mid-Atlantic Ridge was not a sailor himself nor did he have any true scientific evidence that such a thing might exist. Instead, Plato was relating a piece of family legend in a book intended to explore the origins of various people and a means of describing the downfall of a perfect society. In 355 BC, Plato took on the character of Kritias and described the existence once of a city now (meaning in 355 BC) lost forever beneath the waves of the Atlantic in his book Timeaus. According to Plato’s character, “the capital city of Atlantis was a marvel of architecture and engineering.
The city was composed of a series of concentric walls and canals. At the very center was a hill, and on top of the hill a temple to Poseidon. Inside was a gold statue of the God of the Sea showing him driving six winged horses” (Krystek 2006). However, the people eventually became corrupt and greedy and the gods decided to destroy it forever, not only by destroying the city itself, but also destroying any chance that its marvels could be duplicated. This was accomplished 9000 years before Plato’s time, by sinking the island to the bottom of the sea. The significant element of the legend is the location Plato assigned it, right at about the location of the Mid-Atlantic Ridge. Because of this, many have pointed to the Azores Islands, the tallest peaks along the Mid-Atlantic Ridge, as the last remnants of a lost continent or large island.
While this conjecture continues to gather scholarship even into the present day, new and equally fascinating information has been discovered about the Mid-Atlantic Ridge, including its very existence. “The longest single topographic feature of the earth’s solid surface was not known until the present century” (Weintraub, 1979: 77). One of the more troubling phenomena regarding this ridge was what appeared to be the presence of clouds. Upon further exploration thanks to modern technology, it was discovered that these dense black clouds were actually composed of tiny particles of various minerals. All along the Mid-Atlantic Ridge, and other mid-ocean ridges as well, chimney-like structures comprised of sulfide minerals can be found spewing the black smoke into the water.
These chimneys are actually releasing warm, mineral-rich water out into the ocean from beneath the ocean surface. “As the hot, mineral-rich water rushes out of this chimney and mixes with the cold ocean bottom water, it precipitates a variety of minerals as tiny particles that make the vent water appear black in color” (Black Smokers, 1997). It is thought that perhaps cold ocean water is seeping through fissures in the ocean floor into or close to magma chambers lying underneath the ocean ridge. This water becomes heated through the exposure and charged with minerals from the magma and then escapes through the hydrothermal vents or black smokers (Singh et al, 2006). What seems even more surprising about these structures, though, is the life that they support.
Upon visiting the hydrothermal vents, or black smokers, scientists were surprised to discover a wide variety of life forms living along the ridge. They found many animals that were more common to much shallower waters such as clams, mussels, crabs, shrimp, starfish and skates. Tube worms were also found living on the chimneys themselves, apparently able to withstand incredibly high water temperatures (reaching as much as 110° C) without injury (Black Smokers, 1997). Other life forms continue to be discovered, but much of the life found at the Mid-Atlantic Ridge seems to be based upon the lowest element of the food chain, the Archaea, which is a tiny form of bacteria. These tiny life forms “derive energy and nutrition from the hot, mineral-rich waters venting from the sulfide structures. The Archaea use sulfide instead of sunlight to create food, a process analogous to photosynthesis called chemosynthesis” (Black Smokers, 1997). That this was a possibility for creating life had not even occurred to scientists before their discovery in 1977.
Thus, whether it is as a basis for ancient legend and continuing geologic investigation or a site of amazing new scientific discoveries regarding how our planet operates, the Mid-Atlantic Ridge is an important site for geologists. Consistently yielding new information such as the existence of new life based on processes unlike that of most of life on earth, the ridge introduces new conceptions of how life might have started on this planet and provides suggestions that life based upon other processes might exist elsewhere. Meanwhile, continued interest in exploring ancient legends continues to drive further interest in exploring the geographic eccentricities of the Mid-Atlantic Ridge in particular.
Works Cited
“Black Smokers.” American Museum of Natural History Expeditions. (1997). Web.
Krystek, Lee. “The Lost Continent: Atlantis.”Unmuseum. (2006). Web.
Singh et al. “Discovery of a magma chamber and faults beneath a Mid-Atlantic hydrothermal field.” Nature. (2006).
Weinhaupt, John G. Exploration of the Oceans: An Introduction to Oceanography. New York: Macmillan Publishing Company, 1979.