A dive to the ore factories of the deep sea

The controversy about Deep Sea Mining is highlighted by the current negotiations at the International Seabed Authority (ISA) about the regulatory framework for potential future exploitation. An increasing number of countries, including Germany, call for a precautionary pause. However, beyond potential commercial activities, there is great scientific interest in mineral systems at the seafloor: Only here, marine geologists can directly study the active tectonic, magmatic and hydrothermal processes that are relevant for the formation of many metal deposits today preserved in the Earth’s crust. The scientific findings will be used to advance deposit models and to evaluate options for an improved recovery of energy-critical metals and metalloids from existing mine sites on land.

Expedition SO299 DYNAMET with the German research vessel SONNE will head to the Bismarck Archipelago in north-eastern Papua New Guinea to obtain the first comprehensive view of one of the world’s most complex, yet extremely mineral-rich, belts and attempt to address a major unsolved question about the region: Why has so much metal been added to the crust at this location? The cruise is led by Dr. Philipp A. Brandl, marine geologist at GEOMAR Helmholtz Centre for Ocean Research Kiel, Germany, with Professor Dr. Christoph Beier from the University of Helsinki acting as co-chief. In addition, among the 37 participants are also researchers from the GeoZentrum Nordbayern of the Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU) and the German Federal Institute for Geosciences and Natural Resources (Bundesanstalt für Geowissenschaften und Rohstoffe, BGR). Also participating are researchers from the Universities of Ottawa and Toronto in Canada through a collaborative research and training experience project in Marine Geodynamics and Georesources (iMAGE-CREATE) as well as from the University of Papua New Guinea.

Sample collection using highly advanced submarine robotics

After a covid-related delay of two years, the cruise will finally continue research efforts that started during three previous SONNE expeditions in 1994 (SO94), 1998 (SO133) and 2002 (SO166). However, only during the SO299 expedition, state-of-the-art geophysical instruments will be deployed at the ocean floor to detect magma and fluid migration in the crust, trace active fault zones and model the thermal structure of the crust. The central tool is the remotely operated vehicle (ROV) KIEL 6000 from GEOMAR. The underwater robot is able to dive 6000 metres deep and is equipped with high-resolution cameras, sonar, and a variety of sampling tools and in situ sensors. Operated by a group of eight engineers, the highly advanced system allows targeted and visually controlled sampling of individual rocks as well as fluid and gas vent sites.

Metal deposits and hydrothermal vents

“The key aim of our research is to understand how plate tectonic processes may affect the formation of ore deposits near subduction zones. This region is of particular importance because some of the world’s largest copper and gold deposits have formed there and are still forming today”, explains Dr. Brandl. “We are interested in understanding how the tectonic processes influence location and size of mineral deposits. The interaction of seawater with the hot surrounding of the volcanically active seafloor is interesting, because it transfers elements including metals from the rocks below to the seawater and vice versa.” These regions are known as hydrothermal systems and are not only the site of active ore-forming processes but also hotspots of a highly-specialised biodiversity in the deep sea. “Our scientific responsibility thus includes to be least invasive in our research”, adds Dr. Brandl.

Metals for green technologies

The demand in critical and specialty metals and metalloids is expected to continuously rise in response to the further development and increased use of green technologies. “Meeting the conditions for this increasing demand and at the same time making the required raw material supply more responsible requires finding the most suitable resources on land and increasing the efficiency in theirs use”, says Professor Dr. Beier from the University of Helsinki. “For us researchers from Finland, studying ore-forming processes in geologically young terranes and in active systems also advances our understanding of ancient deposits. Many of the mineral resources we have available to us in Finland may have formed in environments comparable to those found in the western Pacific and as such, the present may be the key to the past.”

Expedition SONNE SO299 DYNAMET

06.06.2023 - 29.07.2023

Townsville (Australia) – Singapore