Located some 3 kilometers underneath the surface of the Atlantic Ocean,, scientists have discovered the hottest water ever found on Earth emanating from two black smokers called Two Boats and Sisters Peak. So hot, in fact, that the fluid has moved from being a fluid, to being a supercritical fluid.
A black smoker is a type of hydrothermal vent, a fissure in the planet’s surface, from which water heated by the geothermal heat from beneath issues in to the surrounding water. Geochemist Andrea Koschinsky, from Jacobs University in Bremen, Germany, and her team have been visiting these vents for several years, lowering thermometers in to them to gauge their temperature.
"It's water, but not as we know it," Koschinsky said of her discovery, referring to the fact that the fluid has gone supercritical.
When the temperature and pressures rise in a liquid, evaporation and/or boiling will occur. However, if both temperature and pressure is pushed to a critical point, the gas and the liquid will merge in to what is called a supercritical fluid. This has been done in laboratory and industrial settings, but never before has it been witnessed occurring naturally before.
And Koschinsky believes that this discovery could give us an idea how our oceans end up with traces of gold, copper and iron mixed in.
With the water maxing out at 464 °C for periods of 20 seconds, but settling at around 407 °C, the supercritical water acts different than normal water. It is far less dense than liquid water and vapor, and thus leaches elements like gold, iron, manganese and sulphur out of the rocks far more efficiently than liquid water.
Just why the vents are so hot is at the moment, a mystery. Koschinsky thinks that "the magma body underneath is probably enormous.” However her colleague, Colin Devey of the University of Kiel in Germany is less certain. "The explanation could be that there's lot of magma, but after a few more years of high temperatures, it's going to get to the point where it will be embarrassing how much magma there needs to be to maintain them for that long."
His explanation revolves around the idea that the vents that cool much more quickly in the Pacific, could indicate that the Pacific crust is more water-logged than the Atlantic’s crust. Vents are supposed to cool off after a year or so, but Two Boats and Sisters Peak could have been revitalized after a quake hit the surrounding region back in 2002.
If Devey is right? "If that turns out to be the case then we will have taken down some very, very holy grails," says Devey.
Posted by Josh Hill