New approach to ferromanganese nodules from the Baltic Sea

Polymetallic nodules (including ferromanganese) are one the major metal-bearing sources, those admitted as strategic and critical raw materials (CRMs) by the European Commission. Their widespread on seas’ and oceans’ bottoms entail interests in economic use of them.

Ferromanganese (Fe-Mn) nodules occur on the seabedof most areas of the Baltic Sea. Those from the Polish Exclusive Economic Zone (PEEZ) are ones of least explored elements of the marine environment. Since 2020 there have been 3 research cruises on the area of the PEEZ - on 3 selected areas, 25 km2 each (near Baltic Beta oil rig, Slupsk Furrow and Gdansk’s Basin). Almost 100 sediment samples from the seabed were collected by Van Veen sampler and box-corer. So far, more than 2000 samples of nodules have been described and analyzed.

The main assumptions of the project are to determine:

• mineralogical and chemical compositions, genesis, age;

• geochemical variability of Fe-Mn nodules and their relation to bottom sediments and the morphology of the bottom surface;

• directions for depositional potential based on chemical composition for averaged samples of the areas in the PEEZ.

The chemical investigation (by using of ICP-MS) performed on the new nodule samples from the Słupsk Furrow and the edge of the Gotland Basin showed the average REE content at the level of 164.33 ppm (from 118.40 ppm to 202.74 ppm). There is a visible small positive Li anomaly (from 60.40 ppm to 444.60 ppm).

Further research investigations may redound more data in the context of economic potential.