Metasomatism is the chemical alteration of a rock by hydrothermal and other fluids.

Metasomatism can occur via the action of hydrothermal fluids from an igneous or metamorphic source.

Tremor is commonly associated with the underground movement of magmatic or hydrothermal fluids.

Metal sulfides were deposited by hydrothermal fluids on or in the sea floor of a tectonically-active basin.

The strategy is to look at the usefulness of supercritical hydrothermal fluids as an economic energy source.

This ion is probably important in movement of copper and gold in hydrothermal fluids.

Many mineral deposits are the result of large-scale circulation of hydrothermal fluid in the upper crust.

Metamorphic processes also control many physical processes which form the source of hydrothermal fluids, outlined above.

This data suggests the volcano is actively venting warm hydrothermal fluids.

The fragments have been rounded due to either milling action or corrosion by hydrothermal fluids.