S2.10: Extant and extinct shallow submarine hydrothermal geobiology laboratories and ore-forming systems in volcanic-arcs
Ernest Chi Fru
School of Earth and Ocean Sciences, Cardiff University, United Kingdom
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.