Just off the coast of Washington state, there lies a metropolis of underwater geothermal towers created by searing hot liquids that have emerged from the seafloor due to deep forces of the underworld.
Marine geologists and biologists have recently studied a fascinating portion of the seafloor, known as the Endeavour Segment of the Juan de Fuca Ridge, and developed a new underwater map documenting almost 600 hydrothermal chimneys here.
Known as “one of the most remarkable places on Earth,” scientists have been using submersibles and underwater robots to study the Endeavour Segment of the Juan de Fuca Ridge since the 1980s. This portion of the seafloor, found some 350 kilometers (220 miles) off the Pacific Northwest of America, is the prime spot for hydrothermal chimney-like structures. While the area has been traversed before, its true extent has never been realized until this recent survey since much of the area is shadowed by dark, murky waters. Reported in the journal Geochemistry, Geophysics, Geosystems, multibeam mapping data collected by an autonomous undersea vehicle has been used to create a map of 572 chimneys along the central 14-kilometer (8.6-mile) valley of the segment.
“It’s very hard to see down there because all the particulates in the water create a kind of haze. I remember there was one well-studied chimney where the composition of the fluids seemed to vary from one research dive to the next,” David Clague, the lead study author from the Monterey Bay Aquarium Research Institute, explained in a statement.
“It wasn’t until we did our detailed mapping that people realized they had actually been sampling at two different chimneys. They apparently would encounter one chimney or the other depending on what direction they approached the site.”
The Endeavor Segment is so rich in hydrothermal chimneys possibly because it has experienced minimal eruptive activity over the past 4,300 years, allowing the chimneys to stand tall and become buried, which tends to occur on other ridges.
These chimney-like structures are created by superheated water, hydrothermal fluid rich in minerals like iron sulfide and calcium cooked to over 300°C (570°F) by magma that’s then ejected out of the seafloor from underwater seeps and geysers known as hydrothermal vents. Once the liquid hits the chilly seawater, the minerals solidify and crystallize, forming hard hydrothermal chimneys that reach up to 25 meters (82 feet) tall.
Oceanic hydrothermal vents aren't just interesting from a geological perspective, though. These extreme environments are also believed to have played a fundamental role in the creation of microbial life on Earth, acting as the cooking pot where inorganic chemicals made the leap into organic compounds. As such, researchers study these features to understand how life might come to be on otherworldly planets.