Return to deposit models

Acid Sulphate Model e.g. El Indo (Chile), Goldfield (Nevada)

Adapted from Evans 1997: Ore Geology and Industrial Minerals


Also known as high sulphidation deposits because of the high acid sulphate bearing fluids. Located in calderas or silicic domes and hosted mainly by rhyodacite forming domes and ash flows. The ore has variable gold and silver values with high levels of copper and is situated within the heat source. Mineralisation and host rock are generally of similar age. Alteration near and around the orebody is argillic with alunite and kaolinite, no adularia alteration.

With the convective circulation of meteoric and magmatic waters, elements are leached from the surrounding host rocks and upon cooling are deposited near the surface forming a deposit within the heat source.


Return to deposit models