Scientists from the USGS, the University of California Santa Cruz, Oregon State University, and Scripps Institution of Oceanography have published a detailed study of how the composition of ferromanganese (FeMn) crusts varies along seamounts spanning 30° of latitude in the west-central Pacific.

They evaluated the concentrations of elements (e.g., manganese—Mn, iron—Fe, cobalt—Co, nickel—Ni, molybdenum—Mo, zinc—Zn, silicon—Si, aluminum—Al, barium—Ba, magnesium—Mg) from the uppermost layer (less than 15 millimeters) of 57 FeMn crusts for statistically significant variance and correlation with a variety of oceanographic and geographic parameters. Fluctuations in seawater oxygen content, detrital input, surface productivity, and deep sources of iron are clearly recorded by FeMn crusts. Modern measurements of these primary parameters, as well as paleoceanographic reconstructions, can be used to define regions of interest for FeMn crust exploration.

Map of the western equatorial Pacific region showing ferromanganese (FeMn) crust dredge locations. Inset in the upper right shows the general region of the sample area; different colors for dredge locations indicate the four cruises included in this study, and the areas outlined in white show the samples included in each of the three main sample transects, Marshall‐Gilbert‐Tuvalu (MGT), Samoa, and Howland‐Baker‐Tokelau (HBT); this map was created in ArcGIS and includes GEBCO 2014 bathymetry.

Reference: Mizell, K., Hein, J.R., Lam, P.J., Koppers, A.A.P., and Staudigel, H., 2020, Geographic and oceanographic influences on ferromanganese crust composition along a Pacific Ocean meridional transect, 14 N to 14 S: Geochemistry, Geophysics, Geosystems, v. 21, e2019GC008716, https://doi.org/10.1029/2019GC008716