Isotope composition of neodymium in neo-Archean banded iron formations of Karelia and Kola Peninsula

Studies of three deposits of neo-Archean banded iron formations from the West Karelian domain (the Kostomuksha deposit) and from the Central Kola block (the Olenegorsk and Kirovogorsk deposits) showed a pronounced difference in the isotope compositions of Nd from quartz and magnetite–hematite interlayers. The less radiogenic Nd of iron-containing layers compared to that of the quartz component may be considered as an indication of the formation mechanism of the treated banded iron formations. Thus, silicon-containing layers are related to submarine volcanism and iron was supplied to the sedimentation zone from other sources.