Cyprus-type Massive Sulfide Deposit

Synonym

Bimodal-Mafic type massive sulfide deposit

Synonym

Volcanogenic massive sulfide deposit (semi-interpretative term), Stratabound massive sulfide deposit (descriptive), Stratiform massive sulfide deposit (descriptive), Volcanic-associated massive sulfide deposit (descriptive), Volcanic-hosted massive sulfide deposit (descriptive), Submarine exhalative sedimentary deposit (interpretative)

Required Geological Setting

Caldera complexes

Associated metasomatic zones

High-T silicified zone, Illite-Chlorite zone, Interstratified mineral zone

Occurrence

A type of volcanic massive sulfide deposits associated with ophiolite.

Host of the deposit: Mafic volcanic rocks > Felsic volcanic rocks >> Siliciclastic rocks (Sedimentary rocks)

The host of deposits is composed of large amount of mafic volcanic rocks with minor mafic volcanic and little siliciclastic sedimentary rocks such as shale. The deposit is concordant with the sedimentary structure of the host, and is considered to be formed on the ocean floor of oceanic ridges. Sulfide-Chlorite veins are intruded in the mafic volcanic complex such as pillow lavas at the bottom of the deposit underlied rhyolitic volcanic rocks associated with chlorite-sericite-chlorite-quartz alteration zones. The massive pyrite-pyrrhotite-sphalerite-chalcopyrite block deposits at the top of the rhyolitic volcanic rocks covered with mafic volcanic complex such as pillow lavas. The massive sulfide block is rich in magnetite and pyrrhotite at the bottom, whereas it is rich in pyrite at the top. The whole deposit is again covered with mafic volcanic complex such as pillow lavas.

Mineral Assemblages (Ore)

Magnetite, Pyrrhotite, Chalcopyrite, Pyrite, Sphalerite

Mineral Assemblages (Gangue)

Quartz, Sericite, Chlorite