such systems, which currently cluster around the mid-ocean ridges and deep-sea
submerged volcanoes (seamounts) – where hot magma chambers occur near the
seabed – water circulates down into the crust, becomes heated, and then rises up.
When water is overheated to more than 400°C, it can leach metal ions from the
crust. These ions are then brought to the surface by hot hydrothermal fluids, so
that the steady-state concentrations of metal ions at the orifices of hydrothermal
vents may exceed the equilibrium concentrations because of this continuous supply
[102,178].