Abstract During research expedition SO299 with the German RV Sonne , we discovered the first deep-sea hydrothermal vent system along the Tabar-Lihir-Tanga-Feni island chain in northeastern Papua New Guinea. The Karambusel vent field is hosted by a volcanic center on the western flank of Conical Seamount that formed ~ 89 ka ago. Karambusel is remarkable in that it hosts both a fossil high-temperature, gold-rich mineralization and an active low-temperature (< 51 °C) vent system precipitating arsenic-, antimony-, thallium-, and mercury-rich sulfide minerals. Chemosymbiotic fauna is associated with the vent system and we identified more endemic species than in previous studies on nearby seeps. Our study shows that the magmatic event at Karambusel likely triggered the epithermal mineralization at Karambusel and at the central summit of Conical Seamount. The current hydrothermal fluids originate from condensed magmatic vapor or connate fluids. Gas bubbles were observed at some vent sites and the proportion of methane in the gas phase exceeds that of any other hydrothermal vent system. The composition of the light hydrocarbons points towards a thermogenic origin. Karambusel is thus the first hybrid magmatic-hydrothermal vent and hydrocarbon seep system discovered globally which explains the highly endemic vent fauna as a consequence of the unique ecological niche.
Brandl et al. (Fri,) studied this question.