RARE-EARTH ELEMENTS AND THEIR POTENTIAL S OURCES IN ORE FORMATIONS FROM THE ATLANTIC SEA-FLOOR

The comparative study of composition of rare earth elements (REE) in F e-Mn formations and phosphorites and their potential sources has been carried out by means of factor analysis. These potential sources inclu d sufrace and deep oceanic waters, various types of bottom sediments a nd sedimentary rocks, biogenic matter, aerosol, and hydrothermal solut ions. According to degree of similarity with potential sources, four t ypes of REE patterns in ore formations have been identified. It was fo und that hydrothermal source may influence the REE composition in hydr ogenetic Fe-Mn crusts, some of hydrothermal crusts and some of Fe-Mn n odules.