Hydrothermal circulation occurs when seawater penetrates into the ocean crust, becomes heated, reacts with the crustal rock, and rises to the seafloor. Seafloor hydrothermal systems have a major local impact on the chemistry of the ocean that can be measu
from seawater (e.g. Mg, SO4) and adds many others (He, Mn, Fe, H2, CO2), it is an important process in governing the composition of seawater.
Submarine hydrothermal systems are an integral component of crustal construction along the global system of mid-ocean ridges.
Thermally-induced circulation of seawater through the permeable parts of the crust and upper mantle has been estimated to account for 34% of
the predicted global oceanic heat flux, which in turn comprises close to 25% of the total heat flux of the Earth [ Stein and Stein, 1994, and
references therein]. Discharge of hydrothermal fluids is manifest along mid-ocean ridges as high temperature (200-400 C) focused and lower
temperature ( C) diffuse fluid flow. Off-axis fluid flow may extend out to the crustal sealing age of 6510 million years, and may be
responsible for more than 70% of the hydrothermal heat flux [ Stein and Stein, 1994].
