Discriminating formation and accumulation processes of some strategic metals in Fe-Mn deposits of the Atlantic Ocean

This study aims to present the results of inductively coupled plasma mass spectrometry (ICP-MS) determination of economically significant metals including rare-earth elements and Y (REY), Co + Ni + Cu obtained from the Fe-Mn deposits (FMD) of different areas selected along the Atlantic Ocean.

The description of the instrumental part of the analysis was shown in detail, including the choice of the acquisition mode and other settings of the quadrupole ICP-MS Agilent 7700x, which allow to eliminate spectral overlaps as much as possible and to achieve good precision and accuracy of the measurement. The accuracy of the obtained results was controlled by analysis of certified reference materials (CRM) of Fe-Mn nodules of the US Geological Survey – NOD-A-1 and NOD-P-1, as well as the Russian CRM samples of Fe-Mn nodule OOPE 603 (SDO-6) and ore crust OOPE 604 (SDO-7). Statistical processing of the analysis results demonstrated the acceptability of chosen sample preparation technique and ICP-MS tunes for the determination of REY in FMD.

The performed analytical research allowed giving a geochemical characteristic of studied FMD. The precision for the elements to be determined according to the relative standard deviation (RSD) was within 5.0%.

To move away from the subjective visual assessment of the analytical results quality in terms of absence (or presence) of the REE sawtooth distribution, an original objective mathematical method was proposed.