Mineralogy and Geochemistry of the Polymetallic Nodules of the Clarion-Clipperton Zone, NE Pacific

The aim of this master's thesis was the mineralogical and geochemical study of polymetallic nodule samples from the Clarion-Clipperton Zone in the northeastern Pacific Ocean. The samples were analyzed using a range of analytical methods. The mineralogical composition was determined through the XRD analysis, while their geochemical composition was assessed using the XRF and ICP-MS techniques, providing information on the concentrations of major elements and trace elements, including rare earth elements. SEM analysis made the study of the nodules’ microstructures and the composition of the individual layers of the nodules possible, through high-resolution imaging. Additionally, the micro-XRF technique provided elemental maps that revealed the internal elemental distribution within the samples. The combined results of these analyses led to valuable conclusions regarding the formation process of the nodules, as well as the prevailing geochemical conditions during their development. It was concluded that the nodules are of mixed origin, having formed through a combination of hydrogenetic and diagenetic processes. Furthermore, the geochemical conditions during their formation ranged from oxic to suboxic.