Hydrothermal vent areas have hydrothermal chimneys, from which hot, mineral-rich water comes out. (This hot water often looks like black smoke, but it's not really smoke, it just has a lot of dark, microscopic mineral grains in it.) Where does this hot water come from

This water comes from the depths of the earth, where it was heated by the heat of terrestrial magma.

Explanation:

Hydrothermal chimneys are common in hydrothermal ventilation areas, as shown in the question above. These chimneys form at the bottom of the sea and usually spew hot water, which can reach 400 degrees Fahrenheit, full of dark minerals, which promote the characteristic color of this water. To reach such high temperatures, seawater descends into the depths of the earth through cracks in the planet's surface. There, they are heated by magma and return to the surface where they are expelled with a high temperature.