Chemical analysis of micro-samples taken from different outer surface regions of oriented manganese nodules from Northeast Equatorial Pacific

Manganese nodules have been shown to consist of heterogeneous mixtures of a variety of biogenic, detrital and authigenic particles in a finely laminated structure. On a microscale those laminations exhibit variations in Mn, Fe and trace metal concentrations which perhaps reflect changing environmental conditions on the sea floor or in the rain of particles that fall on the nodule. Local X-ray fluorescence analysis reveals that the bottom of nodules are enriched in Mn, Ni and Cu while being relatively depleted in Fe, whereas the opposite pattern is evident for the top of the nodule. The equatorial rim demonstrates the most variable distribution of the elements in relation to other areas on the nodule.