Respuesta :
The particles are predominantly very fine-grained sulfide minerals formed when the hot hydrothermalfluids mix with near-freezing seawater. ... The cold seawater is heated by hot magma and reemerges to form the vents. Seawater in hydrothermal vents may reach temperatures of over 700° Fahrenheit
The answer is:
Friction heats the water as it seeps into holes and cracks on the ocean floor.