Numerous studies on submarine iron-rich sediments (BIF, ironstones, etc.) focus on environmental changes and ocean chemistry, however, many questions related to underlying hydrothermal processes remain unresolved. As proximal chemical sediments, Lahn-Dill-type iron ores can provide insight into mechanisms of hydrothermal seafloor alteration related metal scavenging, and subsequent Fe-mineral deposition. Lahn-Dill-type iron ores formed during the Middle/Upper Devonian within the Rhenohercynian back-arc basin associated with intraplate alkali basaltic volcanism. Ores formed on top of volcanogenic successions...