In some areas along the Mid-Ocean Ridge, the gigantic plates that form the Earth s crust are moving apart, creating cracks and crevices in the ocean floor. Seawater seeps into these openings and is heated by the molten rock, or magma, that lies beneath the Earth s crust. As the water is heated, it rises and seeks a path back out into the ocean through an opening in the seafloor. Yet this water does not boil because it is under so much pressure from the tremendous weight of the ocean above. When the pressure on a liquid is increased, its boiling point goes up.
Chimneys top some hydrothermal vents.
So-called black smokers are the hottest of the vents. They spew mostly iron and sulfide, which combine to form iron monosulfide. This compound gives the smoker its black color. White smokers release water that is cooler than their cousins and often contains compounds of barium, calcium, and silicon, which are white. A scientist at the University of Washington has been monitoring the growth of Godzilla, a vent chimney in the Pacific Ocean off the coast of Oregon.