The Norwegian Petroleum Directorate (NPD) completed a successful data acquisition expedition on the Mohns Ridge in the north-western Norwegian Sea, using the Seabed Constructor vessel, during their four-week expedition.
3,900 line kilometres of geophysical seabed data was acquired using three AUVs operating simultaneously, collecting data as they passed about 50 meters above the seabed at a speed of three knots. The data acquisition has provided seabed maps with a resolution of one meter in water depths up to 3,000 meters.
According to NPD, they discovered the previously unknown sulphide deposits, such as metals and minerals that are important in battery technology, wind turbines and mobile telephones, and collected data covering large areas.
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Moreover, NPD used rock samples using ROVs, that provided large volumes of still-image photographs and HD video were shot to document the mineral deposits.
The NPD has been assigned to map and provide deep sea mineral deposits by the Ministry of Petroleum and Energy.
Exploration director at the NPD, Torgeir Stordal, stated
This is a ground-breaking cruise, in that it is the first time so many autonomous vehicles have been used simultaneously for systematic large-scale mineral mapping. This makes it possible to cover large areas in a short amount of time, so we can streamline and accelerate deep sea data acquisition.
NPD explains that the Mohns Ridge is an oceanic spreading ridge that separates two tectonic plates, and the sulfide minerals are precipitated on the seabed. This takes place after seawater penetrates down into the seabed over underlying magma chambers. There the seawater is heated to more than 300 degrees Celsius and leaches out metals that are then transported up in hot springs on the seabed, where they are precipitated. Such springs build chimney-like mineral structures. These collapse at regular intervals, creating gravel piles – which the NDP sampled.
Concluding, the data acquisition cruise was carried out by Ocean Infinity using the Seabed Constructor, with experts from Ocean Floor Geophysics and the Norwegian Petroleum Directorate. PhD candidates from the University of Bergen (UiB) and NTNU were also invited on the cruise.
