The distribution of rare earth and other elements and the mineralogy of the iron oxyhydroxide phase in marine ferromanganese concretions from within Slupsk Furrow in the southern Baltic

Rare earth element concentrations in ferromanganese concretions sampled from Slupsk Furrow in the Polish Exclusive Economic Zone are similar to those of concretions from the Gulf of Bothnia. The lack of positive Ce anomalies in the concretions from Slupsk Furrow indicates that they are formed under less oxidizing conditions than spheroidal concretions from the Gulf of Bothnia. Mössbauer studies indicate that poorly crystalline lepidocrosite is the principal iron oxyhydroxide mineral present in these concretions.