Epithermal deposit

A deposit formed at shallow depth (less than about 1.5 km) by hydrothermal fluids at 150 to 300 °C, in a volcanic setting. Depending on the sulfur state of the fluid, low-, intermediate- and high-sulfidation types are distinguished. Grades are often high but volumes smaller than for porphyries.

Composition

Metals: Au, Ag (Cu, Pb, Zn, Sb, Hg). Minerals: quartz, adularia or alunite depending on type, argentite, electrum, pyrite, enargite (high sulfidation).

Sources

In the atlas

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