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The Actively forming Sulfide mineralization in the Kolumbo volcano (ASK): source of metals in shallow marine magmatic-hydrothermal systems

Kolumbo is a shallow, submarine volcano, located in the south Aegean volcanic arc (Fig. 1-A). It hosts an active hydrothermal system currently forming polymetallic massive sulfides on the seafloor (SMS) with anomalously high As, Ag, Au, Hg, Sb and Tl contents. It is one of the few known SMS deposits associated with continental margin volcanism. The Kolumbo hydrothermal system represents an active analogue of hybrid epithermal-VMS mineralization style. The particular geological setting of the Kolumbo volcano in the Anydros Basin makes it an excellent natural laboratory to investigate the metal flux and potential source rocks as the underlying units crop out on the neighboring islands of Santorini, Ios and Anafi (Fig. 1-B).

The metal sources and mobilizing processes involved in hydrothermal system are yet not clearly identified. The lithological diversity of the basement and volcano-sedimentary fill of the Anydros Basin provide various potential metal sources, either by leaching with magmatic-hydrothermal fluids or by contamination of the melt by assimilation (Fig. 1-C). The magma can also release metals during magmatic degassing and contribute to the metal budget (Fig. 1-C). Constraining the metal reservoirs involved in magmatic-hydrothermal systems is crucial for understanding the formation of SMS and the variability in the metal endowment between the deposits.

This project will greatly improve our comprehension of the geochemical path of the epithermal suite of elements in a continental margin environment and will improve our models for the poorly known hybrid epithermal-VMS deposits.

Figure 1- (A) Map of the Aegean Sea, showing the South Aegean volcanic arc, its volcanoes and the location of the study area; (B) Geological setting of the Kolumbo volcano and stratigraphy of the basement. The lithologies of Ios, Santorini and Anafi corresponding to the different units of the basement are shown by arrows (modified after Druitt et al. 1999; Flansburg et al. 2019; Sakellariou et al. 2010; Soukis and Papanikolaou 2004). The dot-line shows the cross-section; (C) Model of the Kolumbo hydrothermal system and processes involved in the SMS (modified after Kilias et al. 2013).



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Kilias SP, Nomikou P, Papanikolaou D, Polymenakou PN, Godelitsas A, Argyraki A, Carey S, Gamaletsos P, Mertzimekis TJ, Stathopoulou E, Goettlicher J, Steininger R, Betzelou K, Livanos I, Christakis C, Bell KC, Scoullos M (2013) New insights into hydrothermal vent processes in the unique shallow-submarine arc-volcano, Kolumbo (Santorini), Greece. Sci Rep 3:2421.

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Publication from this project

S. Hector, C. G. C. Patten, S. P. Kilias, P. Nomikou, J. Kolb & D. Papanikolaou (2021) Metal sources in the actively forming seafloor massive sulfide deposit of the Kolumbo volcano: Insight from the basement rocks. Conference paper, GeoKarlsruhe 2021, Karlsruhe, Germany.