Shallow Drilling of Seafloor Hydrothermal Systems Using the BGS Rockdrill: Conical Seamount (New Ireland Fore-Arc) and PACMANUS (Eastern Manus Basin), Papua New Guinea

Abstract

From September to October 2002, shallow drilling, using the submersible (5 m) Rockdrill of the British Geological Survey and the German R=V Sonne revealed critical information on the subsurface nature of two distinct hydrothermal systems in the New Ireland fore-arc and the Manus Basin of Papua New Guinea. Drilling at Conical Seamount significantly extends the known surface extent of the previously discovered vein-style gold mineralization (up to 230 g=t Au) at this site. Drilling the conventional PACMANUS volcanic-hosted massive sulfide deposit recovered complexly textured massive sulfide with spectacular concentrations of gold in several core sections including 0.5m@28 g=t Au, 0.35m@30 g=t Au, and 0.20m@57 g=t Au. Shallow drilling is a fast and cost efficient method that bridges the gap between surface sampling and deep (ODP) drilling and will become a standard practice in the future study of seafloor hydrothermal systems and massive sulfide deposits.