I predict that it is coming from the pressure under the ground that makes it warm.
A natural spring is the point at which sub-surface ground water emerges from underground. Precipitation is absorbed into the ground by infiltration. If the water hits a non-permeable layer underground (say, clay or fine grained shale) it will flow laterally and sometimes re-emerges in the form of a natural spring.
The term for groundwater heated by magma that rises to the surface and collects in a natural pool is "geothermal hot spring." These hot springs are formed when the heated water finds a pathway to the surface, creating pools of warm water that people often use for relaxation and therapeutic purposes.
A hot spring that erupts through clay is known as a mud pot or mud spring. The clay acts as a natural seal over the hot water below, causing it to push its way through the clay surface, often creating bubbling mud pools. Mud pots can be found in geothermal areas with high heat and water content.
firefly etc or hot spring
A geyser is a hot spring that erupts releasing water and steam. There are geysers in North America, Asia, Australia, and South America.
There is no natural hot water occurring in the Antarctic.When hot water is required, heat is applied to ice, which is abundant.
Geyser
None. Spring water has a higher level of minerals, but minerals are not calories.
It is warmed by geothermal energy which is created by RADIOACTIVE DECAY http://en.wikipedia.org/wiki/Geothermal_(geology)
A spring is any natural situation where water flows from an aquifer to the Earth's surface. There is no special 'legal definition'. However, the laws in any particular jurisdiction can affect the owner's rights to divert or change the flow of water from the spring.
what causes a hot spring
It's called a geyser.