Researchers from the University of Southampton have discovered a new type of hydrothermal vent that has an unusual structure unlike anything ever seen before, and according to a new study they were formed of primarily talc instead of the typical sulfide minerals.
Writing in a recent edition of the journal Nature Communications, postgraduate research student Matthew Hodgkinson from the university’s National Oceanography Centre Southampton and his colleagues explained that the newfound vents are unlike any active vent field ever discovered.
The vents discussed in the study were discovered in the Von Damm Vent Field (VDVF), south of the Cayman Islands, by scientists and the crew of the RRS James Cook in 2010. Between 85 and 90 percent of their composition by volume was of the silicate mineral, talc, they said.
“This vent site is home to a community of fauna similar to those found at the Mid-Atlantic Ridge in the Atlantic Ocean,” Hodgkinson explained in a statement, “but the minerals and chemistry at the Von Damm site are very different to any other known vents.”
VDVF may not be the only vent field of its kind
Hydrothermal vents form in regions where tectonic plates spread, which causes magma below the seafloor to heat up circulating seawater and make it more acidic. As a result, the surrounding rocks are stripped of their metals, and those metals are then redeposited as the hot water flows out of “chimneys” or vents in the seabed and comes into contact with the cold seawater.
In the case of the VDVF system, there is also a energetic heat flux (the amount of energy emitted into the surrounding ocean) that reaches levels of about 500 megawatts—far more than an expert would expect, given that the VDVF is located on the slope of an underwater mountain and on the edge of a spreading area and not between two separating plates or near a large magma reserve.
The vent field’s unorthodox positioning indicates that the there may be other, similar features to be discovered elsewhere in the world, Hodgkinson said. If they do exist, he added, “they could be important contributors in the exchange of chemicals and heat between the Earth’s interior and the oceans, and may be missing from current global assessments of hydrothermal impact on the oceans.”
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Feature Image: Wikimedia Commons
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