NPD Deep Sea Minerals Search Identifies New Targets
The Norwegian Petroleum Directorate said it has identified a large area of sulphide minerals following a three-week data acquisition expedition on the Mohn’s ridge in the western part of the Norwegian Sea.
The deposits could include important industrial metals such as copper, zinc, cobalt, nickel, vanadium, wolfram and silver.
The NPD has been assigned the task of proving and mapping deep sea minerals after the Ministry of Petroleum and Energy was given administrative responsibility for mineral deposits on the Norwegian continental shelf.
During this year’s expedition, the NPD surveyed an area of 90 km x 35 km centrally located over the spreading ridge, where water depths vary between 1200 and 3500 metres. The expedition was conducted with the Seabed Worker vessel, which is owned by Swire Seabed.
The mapping was carried out using an autonomous underwater vehicle, Kongsberg Hugin AUV, which mapped the seabed in long corridors, totaling 750 kilometres. The AUV was equipped with several sensors, including seabed penetrating echo sounders. Other types of data collected include multibeam bathymetry, synthetic aperture sonar data, magnetometry and spontaneous potential field data. The AUV was operated by Ocean Floor Geophysics.
The seawater penetrates deep into the seabed, is heated to more than 400 degrees by underlying magma chambers, and dissolves many minerals. The warm seawater is flushed back out to the seabed through so-called “black smokers” where the minerals are precipitated in contact with the cold seawater. When the magma chambers shift due to the spreading between the plates, the flushing of the warm water stops, and the black smokers collapse and ultimately end up as piles of gravel on the seabed.
The new area of sulphide minerals that was discovered is said to contain many piles of gravel and collapsed black smokers, including a 26-metre high, non-active tower, in addition to some active systems. The mineral samples taken from these piles of gravel will now undergo several analyses. All mapping data from the AUV sensors will also be processed and interpreted.
Exploration director Torgeir Stordal in the Norwegian Petroleum Directorate said: “It is gratifying that we have found a completely new deposit. We have also tested a number of measurement and mapping techniques that will be useful in future data acquisition expeditions.”