Hot Springs

The occurrence of hot springs is also strongly correlated with volcanism. In continental areas with no volcanism, the temperatures of springs seldom exceed 293 K. Most boiling hot springs and geysers are directly associated with the cooling of a magma body at a relatively shallow depth. The circulation of heated ground water near a cooling intrusion ac celerates the solidification of the intrusion and plays an important role in the emplacement of ore deposits. Minerals dissolve in the hot water; when the water boils or is cooled, the minerals precipitate to form ore deposits. Hydrothermal circulation of seawater in the oceanic crust also is believed to play a significant role in removing the heat at ocean ridges and in concentrating minerals on the seafloor and in the oceanic crust. Exploration with the deep submersible Alvin has provided actual observations of hot water from the crust venting directly to the ocean. Submarine thermal springs have been discovered on the Galápagos rift and the East Pacific rise crest. Spectacular submarine hot springs with exit water temperatures near 700 K have also been discovered at the latter location.