S2.10: Extant and extinct shallow submarine hydrothermal geobiology laboratories and ore-forming systems in volcanic-arcs


Stephanos Kilias

National and Kapodistrian University of Athens, Greece

Jonathan Naden

British Geological Survey, United Kingdom

Ernest Chi Fru

School of Earth and Ocean Sciences, Cardiff University, United Kingdom

Magnus Ivarsson

Department of Biology, University of Southern Denmark, Denmark / Department of Palaeobiology, Swedish Museum of Natural History, Swede

Modern and fossil geothermal systems associated with shallow submarine and emergent arc-volcanoes constitute sources of seawater acidity, energy donors for marine microbial communities and, analogues for ore-forming systems that have produced minable metal deposits; these attributes result from a complex and dynamic interplay between geothermal, metallogenic, biological and volcanotectonic processes. The Aegean is a world renown type locality for interdisciplinary data derived from such systems associated with shallow submarine (<500m) (Kolumbo, Santorini) and submarine-to-subaerial (Milos) components of the Aegean Volcanic Arc (HVA), S. Aegean Sea, Greece. Actively forming polymetallic seafloor massive sulfide mineralization at Kolumbo, is enrichedin critical metals/metalloids (Sb, Tl, Hg, As, Au, Ag, Zn) and exemplifies mineralization across the submarine-subaerial transition, whereas at Milosthis style of mineralization has been uplifted and preserved intact providing on-land analogue of hybrid epithermal-to-VMS mineralization. Milos hosts the first identified <1 Ma biogenic fossiliferous sedimentary iron formation comparable to Precambrian banded iron formations (BIFs); Santorini caldera,may constitute potential analogue for geobiological formation mechanisms of Fe-rich chemical sediments in the Precambrian rock record. Ore-grade Mn-Ba beds, associated with the Milos IF, typify Microbially Induced Sedimentary Structures formed due to interaction of littoral sedimentation, white smokers and active photosynthetic and/or chemotrophic microbial activity. We welcome contributions from the Aegean or elsewhere, related to the implications of such systems for understanding ocean acidification and CO2< leakage and benthic accumulations from subsea carbon capture and storage sites, Fe-Mn biomineralization, submarine metallogenesis, volcanic hazard preparedness, and submerged metal and critical raw material resource potential.

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