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Hydrothermal metallogenic processes off the islands of Nisiros and Kos in the Hellenic Volcanic Arc

1991; Elsevier BV; Volume: 99; Issue: 1-2 Linguagem: Inglês

10.1016/0025-3227(91)90086-j

1872-6151

S.P. Varnavas, D.S. Cronan,

Marine and environmental studies

Two submarine hydrothermal fields off Nisiros and Kos islands in the eastern sector of the Hellenic Volcanic Arc have been investigated using analyses of submarine hydrothermal waters and sediments. Both the waters and the sediments were found to be enriched in Fe, Mn and Zn, together with As, Mo and V in the sediments only, resulting from seawater-rock interaction processes similar to those described from mid-ocean ridge systems. Differences found between the products of these processes in the two hydrothermal fields studied reflect differences between the rock types being leached, the physiographic and geological conditions present including the thickness and composition of the sediment column above the volcanic rocks, and the rates of mixing of hydrothermal solutions with normal seawater. The geochemical features described support possible sub-seafloor formation of metal sulphides at both of the hydrothermal fields studied.