Page 30 - Super Earth Encyclopedia

SUPERHEATED WATER

Volcanoes are the most dramatic features of Earth’s
tectonic plate boundaries and hotspots. But molten
rock rising through the crust can also heat water that
has seeped into the ground. Since hot water tends to
rise, it finds its way back to the surface, where it erupts
as hot springs, geysers, and other geothermal features.
Unlike most volcanoes, they are often constantly active.

HIGH PRESSURE

All geothermal features are caused by water being heated
deep below ground. The high pressure at depth enables the
water to be superheated to well above its normal boiling
point. This makes it dissolve minerals from the rocks. The
hot, mineral-rich water rises through vents, often forming
hot springs or escaping as steam at fumaroles. Pressure
building up in the vents can power spectacular geysers.
Chemicals in the water may also attack the rock and turn
it to hot liquid mud that bubbles up as mudpots.

This geyser erupts at
frequent, regular intervals,
exploding from a vent in the
floor of a shallow pool.

Water often turns to
steam before it reaches
the surface, and erupts
from a fumarole.

When some of the hot
water in this chamber
escapes, pressure
drops. This allows
water below to boil
and erupt as a geyser.

The weight of hot water in
the chamber above makes
GEOTHERMAL FIELDS pressure build up in this vent,
heating water to above
normal boiling point.
Most hot springs, geysers, and similar features
occur where the plates of Earth’s crust are
pulling apart. They include these fumaroles in Volcanic sulfur gas dissolved
Iceland, as well as the black smokers that erupt in water creates sulfuric acid.
This turns porous rock to mud,
from mid-ocean ridges. But some of the most which bubbles from a mudpot.
famous are fueled by the heat of dormant
supervolcanoes such as Yellowstone in the US.
Magma deep below ground
All these features are often grouped together heats this rock, and the water
in clusters called geothermal fields. in the porous rock above it.

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