Original paper

Geochemistry of the Serifos pluton (Cycladic islands) and associated iron oxide and sulfide ores: Skarn or metamorphosed exhalite deposits?

St. Seymour, Karen; Zouzias, Dimitrios; Tombros, Stylianos; Kolaiti, Eftyhia


In Serifos island a mid-Miocene pluton was emplaced syntectonically at ca. 11 Ma in a northeasterly trending fault zone within schist and marble of the Cycladic Blueschist Unit. The central mass of the pluton consists mainly of hornblende-biotite granodiorite and less tonalite, its border facies is granodiorite to granite. Associated dykes are mainly granodioritic. Amphibole geothermobarometry indicates pluton emplacement at initial maximum P ≈ 3.1 ± 0.6 kbar and T between 748° to 718 °C under hypersolvus conditions. Magnetite-hematite ores, which have been mined since antiquity, occur in the proximity of the Serifos pluton. Most of iron oxide ores are located in marble within the contact metamorphic aureole and have been considered as skarn deposits. However, a few iron oxide and base metal sulfide deposits occur outside the contact aureole. The trace element (V, Ti, Ni) characteristics of the iron ores suggest a sedimentary provenance. The sulfide ores are folded and because the geochemistry of some of the schists of the encasing Blueschist Unit shows them to be of possible metavolcanic origin, on alternative exhalite genesis is suggested for these Serifos ores.


magnetite-hematite oressulfide orevolcano-sedimentary protolithsgranodiorite