Vanuatu – Hydrothermal Metallogenesis

Country / Region: Pacific Ocean

Begin of project: June 1, 2013

End of project: July 31, 2015

Status of project: September 11, 2014

The BMBF-funded Project “Vanuatu – Hydrothermal Metallogenesis” is an joint research project of BGR, the University of Erlangen-Nürnberg, and the Jacobs University Bremen. In July 2013, BGR started to investigate hydrothermal sulfide occurrences within the so-called Coriolis Troughs located east of the Republic of Vanuatu in the SW Pacific (Fig. 1). Subduction of the Australian plate beneath the Pacific plate causes the formation of volcanic rocks with a special composition that is thought to be related to the ore-forming processes. Comparable conditions lead to the formation of the Ladolam deposit on Lihir Island (Papua New Guinea) which is host to one of the world’s largest gold enrichments.

Fig.1 - Working area located in the SW-Pacific Source: BGR, GoogleEarth

The main objective of this study is to identify the processes which lead to the formation of polymetallic sulfides and the so-called black smoker chimneys which were recovered from a water depth of about 2,000 meters (Fig. 2). In addition to the hydrothermal precipitates and the hot fluids (up to 370 °C), the volcanic rocks in immediate vicinity of the vents are a matter of interest as well. The selective sampling and detailed analysis provides information on availability, transport, and enrichment of economically important elements including Cu, Zn, Pb, Au, Ag, Ga, Ge, and In. Finally, the results are going to enhance the general understanding of the formation of massive sulfide deposits.

Fig.2 - Sulfide chimneys in a water depth of 1,880 m Source: BGR, GEOMAR

During the expedition, important exploration techniques which are also in use at other localities (see INDEX-Project) were applied, refined and improved. The project is accompanied by extensive environmental examinations of the vent sites and their surroundings.